How do you solve a problem like Lionel Messi?
The world’s greatest player meets the Premier League’s meanest defence on Wednesday night, as Barcelona and Liverpool prepare for what promises to be a genuine classic at Camp Nou.
And if the Reds can keep Barcelona’s No.10 quiet, then No.6 will feel a whole lot closer.
There are not many teams Messi has failed to score against during his illustrious career, but Liverpool are on the list. The Argentine genius faced the Reds twice in the 2007 Champions League, starting both legs of a last-16 tie that the Reds eventually won on away goals.
Both Jamie Carragher and John Arne Riise played in those games, including a memorable 2-1 win for the Reds at Camp Nou. Riise, of course, scored the winner that night.
“It was the only goal I ever scored in my career with my right foot!” he tells Goal. “It was one of the great moments for me.”
Messi, meanwhile, was a peripheral figure across both matches. A stumpy, long-haired 19-year-old stationed on the right flank, he was shackled expertly in the first leg by Alvaro Arbeloa, who was making his first Reds start in the unfamiliar position of left-back.
“I remember Rafa Benitez pulling Arbeloa while we were having a pre-match walk,” says Carragher. “He told him he was playing left-back, which was a bit of a surprise.
"Rafa had a reputation of being very considered and of planning weeks in advance, but he was capable of springing a surprise on the day of games too.
“Messi wasn’t the main man back then – it was Ronaldinho’s team really – but we all knew about this kid coming through who was going to become a superstar.
"Obviously we knew he played on the right and cut inside, so Rafa’s idea was to have Arbeloa on his stronger side dealing with that. Every time Messi cut in, it would be onto the defender's strong foot.”
Like so many of Benitez's plans around that time, it worked.
“Arbeloa was brilliant,” says Riise, who played ahead of the Spaniard as a left-sided midfielder.
“He was so good at reading the game and getting tight to his winger to shut down the space, and he did it all night. I think it helped that we had basically two left-backs playing.
"He knew I would run and cover him, and I knew that if I went forward, he would be there behind me to defend.”
Messi, of course, is a different proposition now. He’d played just over 50 times for Barcelona the last time he faced Liverpool. Now he’s closing in on 700 appearances, and needs two goals to reach 600 for the club.
Since 2008, he has scored a minimum of 38 goals a season; this time around he has 46 in 45 appearances. He is, in every sense, a remarkable footballer.
So, how do you stop him?
“For me, everything depends on how compact Liverpool can be,” Riise says. “We know that Messi is the key to everything.
“What did we see against Manchester United in the last round? He only needs one chance to get the ball and turn, and suddenly things will happen.
"He was quiet at Old Trafford until he got one opportunity and he created a goal. Then, in the Nou Camp, he took the tie away in the space of a few minutes.
"So, you have to be compact and make the pitch as small as possible.”
Carragher, who was undefeated in three trips to Camp Nou with Liverpool under Benitez and Gerard Houllier, agrees with his former colleague.
“One thing that never changes in football is that if you’re not compact, you can’t defend effectively,” he says. “You have to close the gaps and the space.
“The genius of Messi, of course, means that even the best-laid plans can go out the window. What makes him special, the best in my view, is that he can hurt you without space.
"He only needs half a yard and he can beat two or three and open the game up. In tight areas, there is nobody better.”
Would he, then, consider a man-marking job on Barcelona's star man?
“I don’t think Jurgen Klopp would ever do that,” he says. “But he will certainly want to try and stop [Sergio] Busquets from getting on the ball.
"Whether [Roberto] Firmino plays or not, he’ll want someone in and around Busquets trying to disrupt him and stopping him building the game. If you can do that, you have won a big part of the battle.”
Both Carragher and Riise believe Liverpool’s midfield selection could hold the key.
Klopp has tended to lean towards the tried and trusted trio of Jordan Henderson, Gini Wijnaldum and James Milner for big European away games, with mixed success, but both Naby Keita and Fabinho have made compelling cases for inclusion of late. Keita, in particular, would be a bold selection.
“A big thing for me will be who plays on the left of the midfield three for Liverpool,” Carragher says.
“Keita has played there of late and he’s done very well; he’s improving week by week.
"But for a game like this, against opponents like this, I think Klopp will be tempted to go back to what he knows best, and that means maybe Wijnaldum there or Milner.”
Whoever plays there, Riise says, will need to offer constant support to left-back Andy Robertson, who is likely to find himself directly up against Messi more than most.
“You cannot defend Messi 1v1,” he laughs. “That just doesn’t work.
“So, if Robertson goes out to him, he needs to be covered, either by Van Dijk behind him, Mane in front of him, or one of the midfielders next to him. They have to get bodies around him, every single time.
"You saw what Messi did to Phil Jones when he got him 1v1. People laughed at Jones, but he does it to everybody!
“You have to keep the lines tight, make it hard for Barcelona to play the ball into his feet and find him in space. It means a lot of discipline, a lot of hard work and a lot of running, but it could be the key to everything.”
It promises to be a fascinating night. Liverpool handled trips to Munich and Porto with confidence and conviction, but they will know that Barcelona represents another step up in class.
Messi is waiting, the world is watching. Can the Reds deliver again?