Barcelona make a half-hearted late probe for a third, but they don't get it and the full-time whistle is blown.
We're into the penultimate minute of the match.
The home fans have started to make their way to the exits, and the Bernabeu's blue seats are clearly visible.
Substitution David Villa Sergi Roberto
Late change for Barcelona. Off comes David Villa, with 19-year-old Sergi Roberto coming on to makr his second top team appearance for the guests.
Madrid look dispirited now; their chasing isn't done with the relish they previously managed.
That was a goal fit to cap this occasion! Now the Bernabeu is almost silenced for the first time all night!
Goal Lionel Messi
MESSI!!!! GOAL GOAL GOAL GOAL!!! That's an absolutely brilliant goal from Messi, who's probably just killed the tie off with a truly memorable strike. Picking up the ball 40 yards out, he glided past two or three challenges before touching the ball by Casillas. Sheer brilliance!
Barca are almost taunting their hosts with their possession play at present. Diarra ultimately gives away a foul in the middle of the park.
Barcelona look happy to maintain comfortable possession. A 1-0 win would suit them perfectly.
Passes completed: Real Madrid 127-482 Barcelona.
Yellow Card Emmanuel Adebayor
In the meantime, Adebayor goes in for a very ill-judged challenge on Busquets. The striker led with his arms and is lucky to avoid a red card! He's booked, though.
Mourinho smiles ruefully on the sidelines as Messi commits a foul and does not see a yellow card.
Afellay has made a real difference down the right. He starts a move that almost ends with Messi being played in down the left. Barca are turning the screw.
Ronaldo makes his first meaningful run of the night, but it's started from the edge of his 18 yard box, rendering his efforts wasted.
It's back to basics for Barcelona, who are content to keep possession in the centre of the park.
Mourinho's men are quickly on the front foot, but Barcelona stand firm easily enough.
That's Messi's 51st goal of the season, and it could be his most important to date!
Assist Ibrahim Afellay
Goal Lionel Messi
GOAL!!!! MESSI!!! After an incisive burst through the middle was blocked, the ball broke out to Afellay on the right hand side. The Dutchman got to the byline and centred for the Argentine to nip in at the near post and side-foot home from close range.
After hitting the wall with his first two efforts, this one powerfully clears the wall, but it flies well over the top.
Referee Stark is having a tough time of it right now. He awards Real Madrid a free kick around 25 yards out as Pique fouls Ronaldo. The Portuguese is again standing over it...
Villa breaks down the left in a promising manner, but a good tactical foul from Diarra prevents the attacker from getting into a dangerous area. The Frenchman was a little lucky to avoid a booking.
Madrid win a free kick, but it's wasted as Alonso's free kick is headed clear at the edge of the box.
Substitution Pedro Ibrahim Afellay
Pedro is taken off to be replaced by Ibrahim Afellay.
Barcelona are once again bossing possession impressively, and their passing now has a good deal more zip to it.
OH... Casillas makes a great left handed save from Villa, who burst into the box down the left. The ball rebounded to Pedro, who couldn't adjust himself in time to steer a header on target.
Every challenge now is greeted with a great jeer of anger from the home fans. Ronaldo wins a soft foul from Puyol and heads just over from the resultant set piece.
Real Madrid have left Adebayor in attack on his own as they attempt to come to terms with their numerical disadvantage.
There didn't seem to be a great deal in the home player's challenge, and Real Madrid have a point. Pepe may have been high, but it didn't appear to be particularly dangerous as he stayed on his feet and appeared to be in control of himself as he stretched for the ball.
Red Card Pepe
Again the players surround the referee. Barcelona players brandish imaginary yellow cards after Pepe clattered Alves. RED CARD!!!
Pedro goes to ground heavily in the box. It's not a penalty as Marcelo won the ball. It was a risky tackle though.
Adebayor has added more energy to the Madrid attack. He closes down Mascherano, whose pass back to Valdes is poor. Under pressure, the goalkeeper kicks clear to touch in an unconvincing manner.
Indeed, Madrid go for the cross, but Valdes claims the ball in a commanding manner.
Mourinho is already barking orders at his substitutes. Another change from the home side is possible.
Yellow Card Javier Mascherano
Pepe draws a foul from Mascherano, which earns the Argentine a booking. The free kick is in a central area 35 yards out - probably too far to think about a shot.
A poor clearance from Valdes goes straight to Alonso, who gives the ball to Pepe. He shows why he's regularly a defender with an ugly over-hit pass that wastes what would have otherwise been a promising chance.
Xavi's free kick into the box is instantly nullified due to a foul from a Barcelona player.
Great jinking run from Messi, who draws a cynical foul from Sergio Ramos. Yellow card for the Spain defender, who is out of the second leg!
Yellow Card Sergio Ramos
Madrid seem to have lifted their tempo and are starting to get a foothold in the match.
The possession statistic is remarkable. Real Madrid 27% Barcelona 73%!
Ronaldo! A long diagonal pass from Alonso causes confusion between Puyol and Pique, who leap to try and win the same ball. By the time the Portuguese gets possession, he's at too tight an angle to make an impression.
The pattern of the game doesn't look like it's going to change much with the interval. Real Madrid have shown signs of being more effective with their direct approach due to Adebayor's physicality.
Reports suggest that it was a comment made by Arbeloa towards Keita that started the half-time brawl.
Ambitious effort from Xabi Alonso, who tries his luck from inside his own half. His effort flies well over.
Messi! Good start to the second half from the visiting side. Messi slides a pass wide right to Pedro, whose cross finds his Argentine cohort. The 50-goal striker pulls the trigger, but his shot is blocked.
Substitution Mesut Özil Emmanuel Adebayor
Barcelona get the second half started.
Real Madrid have withdrawn Ozil, replacing him with Emmanuel Adebayor.
RED CARD!!! It might be half-time, but Barcelona reserve goalkeeper Jose Pinto has been dismissed for his part in the half-time fracas!
As the teams marched off at half-time, there was another melee around the tunnel area, which took around two minutes to clear, highlighting how much this match means to both sets of players.
Not a great deal to separate the sides in the first half. Barcelona started the better of the two outfits, but the hosts finished the half better. Will they maintain that momentum into the second half? Find out in around 15 minutes.
Red Card José Pinto Colorado
Wolfgang Stark blows his half-time whistle with the game scoreless.
DOUBLE SAVE VALDES!!! Ronaldo fires in a fierce shot from 25 yards out. Valdes gets his body behind the ball but can't hold it. The rebound drops to Ozil, but Valdes kicks the German's shot clear too. Had that effort gone in, it would have been disallowed due to offside.
Phew! Free kick to Real Madrid on the left hand side of the park. Ronaldo again drills the ball into the wall. Another waste from the Portuguese.
Yellow Card Daniel Alves
It's starting to get really, really feisty. Dani Alves is booked for a challenge near the left corner, but all the action is in the centre of the field, where all the players are congregated around the prone Busquets. The midfield tried to make something out of nothing and is rightly being ignored by the referee.
After that spell of Real Madrid pressure, Barcelona are on the attack. Messi dances between a couple of defenders, but Marcelo times his challenge well on the right corner of the box.
Yellow Card Arbeloa
This match is suddenly alight. An off the ball incident involving Pedro and Albiol has players from both sides surrounding the referee. In the event, Wolfgang Stark remains cool, booking the home defender.
The free kick is straight into the wall. Disappointing from Ronaldo on that occasion.
Yet another free kick for Real Madrid down the left. Di Maria goes by Alves and collapses to a heap near the corner flag; in truth, there was little contact and the decision is generous. Ronaldo hovers...
The free kick is poor from Alonso, with Xavi heading clear.
Free kick to Real Madrid just inside the Barcelona half. Alonso takes it for Pepe to head at goal, but from around the edge of the box, his effort isn't nearly hard enough to worry Valdes.
Another Real Madrid free kick as Marcelo made a surge forward after getting the better of Alves. This kick is also from the home side's left, though 20 yards closer to goal...
Barcelona remain patient, knocking the ball coolly about their own half.
Messi has a surge through the centre before playing a delightful pass threaded for Villa. Albiol gets across well to cover, saving the home side from a dangerous situation.
Pepe may be a defender habitually, but he's already shown he's keen to get forward. Dani Alves, playing his 150th game for Barcelona, deals well with his threat and earns a goal kick.
Barcelona aren't really making big inroads into the Madrid defence, despite all their possession. Xavi has a shot from 25 yards, but his effort passes well over the top.
Some good pressing from Barcelona, forcing Madrid into some hurried passes in their own half. It doesn't yield anything on this occasion, though the hosts look uncomfortable with visiting players baring down on them quickly.
Nearly half an hour gone, and Real Madrid's main creative player, Mesut Ozil, has barely had a say. Mascherano dispossesses him excellently in the centre of the field.
Madrid build an attack down their right, with Ronaldo getting a rare touch. Arbeloa strays needlessly offside, though, and the momentum is lost.
XAVI!!! Almost from nowhere, Messi prises open the Madrid defence. A lovely reverse pass from 25 yards out picks out Xavi at the edge of the box, but the midfielder's effort is smartly saved by Casillas.
Even when under pressure at the back, Barcelona's defenders look immaculate in possession. With home forwards closing down, on Valdez, the goalkeeper picks out a cheeky pass through the centre of Di Maria and Ronaldo.
After withstanding a couple of minutes of pressure, Barcelona are back on the front foot. Messi attempts an extravagant lobbed pass through to Keita, but Ramos heads clear.
Ronaldo has come to the right hand side of Madrid's front three, doubtless in an attempt to expose Puyol's inexperience at left-back.
The first corner for Real Madrid is taken quickly by Marcelo, whose own industry down the flank drew it. Di Maria tried to beat Keita out wide, but the midfielder dived in to make a fine block.
Good closing down from Di Maria, who forces Valdes into an uncomfortable clearance. Madrid don't make anything of the ensuing throw, which was deep inside Barcelona's half.
At last Madrid get a touch of the ball, but Alonso is extremely wasteful with possession, firing a pass straight out of play.
The whistles ring out from the home fans. They're clearly not impressed by the amount of the ball that Barcelona are seeing; Cristiano Ronaldo's barely had a touch to this point.
Sloppy from Busquets, who passes the ball behind Pedro and out for a throw in. That's the first really disappointing moment from Barcelona, who have otherwise looked accomplished to this point.
Messi goes on another raid, but it's well tracked by Pepe, who's again started promisingly in his new midfield role.
Pique has already tried to hit the long diagonal to Villa on a couple of occasions. The former Valencia man gets the ball under control, but he can't beat Marcelo down the outside.
Lovely football from Barca around the Madrid box. They pick up the pace of their passing and nearly fashion an opening for Pedro on the left. Mourinho's men shift across well to cover the danger.
Diarra commits another foul and must already be nearing a booking. For the first time, the Barcelona fans are audible above the din created by the home crowd, encouraged by their side's start.
Barcelona are certainly the dominant force in the game at this time. The game is being played on their terms, and the hosts are struggling to see any of the ball.
Lassana Diarra has been busy in the centre of the field early on, but on this occasion he gets his challenge on Sergio Busquets wrong. Free kick, which Barca take shot.
Oh... the first moment of real danger! Barcelona funnel the ball out to the right for Villa, who cuts inside Marcelo along the 18 yards box and flashes a left-footed shot wide. Casillas was stretched if the shot had been on target!
Still Madrid seek a touch of the ball. Barcelona look in the mood to be very patient in possession tonight.
Barcelona get a real grasp on the ball in the middle of the park, knocking it about in their customary fashion. Real Madrid are happy to sit in their own half and invite their guests onto them.
Pedro twice receives possession on the left hand side, but the wide attacker can't make anything of the ball, dispossessed by Alvaro Arbeloa.
Barcelona don’t have any players on the disciplinary threshold at the outset – Real Madrid have four.
Sergio Ramos leaps into his first challenge of the evening. Barcelona are given the free kick, but the visiting players appeal to referee Wolfgang Stark for a yellow card that is correctly not forthcoming.
Xavi has the first effort on goal of the evening. From around 30 yards out, the midfielder’s effort was ambitious. Though his shot was well hit, it proved a comfortable save for Iker Casillas. Play quickly sweeps to the other end of the field, and Cristiano Ronaldo tests Victor Valdes in a similar fashion – that’s another easy save.
Puyol does well in his first duel against Di Maria, winning a throw. It promises to be a difficult evening for the Spain defender, though.
Just to confirm that Carles Puyol is starting at left-back for the guests.
Messi gets his first touch of the ball, but Marcelo dispossesses him midway inside the home side's half.
There's already a great intensity to this match. Real Madrid win early possession and earn a free kick on the halfway line, Xabi Alonso drawing a foul from Pedro.
And the team in white get us started, backed by cries of "Madrid! Madrid!" from the stands
Jose Mourinho looks focussed on the sidelines. In the centre of the pitch, the teams are getting ready to start. It'll be Real Madrid to start this game.
The teams troop out to a packed Bernabeu.
The teams are in the tunnel. Real Madrid's players are slapping hands and looking confident. There's less exuberance on Barcelona's side.
There's around 10 minutes left before kick-off, and here's another Twitter comment that is a nice piece of food for thought. "Everyone is talking about CR7 and Messi. But Oezil/Xavi could steal the show tonight," Tweets moeyassir
Remember, you can have your say on Twitter when you use #watchwithgoal
jayhovajiire, meanwhile, doesn't fancy the look of Barcelona's defence: "puyol at left back? CR7'll scamper over to the left soon enough."
AliMohddShahid believes that Jose Mourinho's men hold the upper hand going into this clash: "Barcelona can be the underdogs today by beating Madrid, but tht looks unlikely 1-0 2 Madrid OR a draw for me"
When these sides met at the Bernabeu in the league, the match finished 1-1. Lionel Messi opened the scoring for Barca from the penalty spot, but Cristiano Ronaldo levelled in the same manner for the hosts. In last week's Copa del Rey final, Ronaldo was again on target, deciding the match with an extra-time header.
BARCELONA: Victor Valdes; Alves, Mascherano, Pique, Puyol; Xavi, Busquets, Keita; Pedro, Messi, Villa
REAL MADRID: Casillas; Arbeloa, Ramos, Albiol, Marcelo; Diarra, Alonso, Pepe; Ozil, Ronaldo, Di Maria
Here are the teams who will contest tonight's game from the outset...
These great rivals have met twice before at this stage of the competition. On both occasions, Real Madrid have come out on top and have gone on to win the trophy.
Good evening, and welcome to Goal.com’s live coverage of the Champions League first-leg Clasico. This is the match the footballing world has been waiting for! In this historic sequence of four clashes between Barcelona and Real Madrid, it is the two European fixtures that will have the biggest bearing on the clubs. Join us over the next three hours to discover how the first leg of this tie pans out.
Times In IST
Live Final scheduled Suspended Cancelled Postponed