Flung himself across his goal to keep out a powerful drive from Niang 20 minutes in but was left rooted to the spot just over 60 seconds later after being beaten by an unstoppable strike from Pazzini. Little he could have done about Balotelli's goal either, after being left exposed by his defence at a corner.
Went into the book for a crude challenge on Pazzini that ultimately led to the striker being forced off through injury and was also partially to blame for the former Sampdoria's man goal on account of his poor attempted clearance.
Did a decent job protecting his back four, as well as upsetting Milan's hopes of bossing things in the middle of the park, as evidenced by the tackle that prompted Constant's act of retaliation. Also deserved to get his name on the scoresheet courtesy of a stunning free kick that cruelly rebounded back off the post.
Took a while to get to grips with the attack-minded Constant but when he did, he began to get forward himself down the right wing. However, was sacrificed in favour of an extra forward just before the hour mark.
Defended stoutly enough from start to finish, while he was denied a clear penalty at the other end after being pushed over in the area by Niang.
Did not really put a foot wrong at the back, playing an integral role in keeping Milan's much-vaunted forward line in check for the majority of the game.
Charged with the task of keeping tabs on Milan's livewire right-back De Scgilio, the former Rossonero did a decent job in that regard, as well as getting forward himself at every opportunity. His delivery left a lot to be desired, though.
Buzzed about in behind the front two, but never actually managed to create any clear-cut openings for his forwards.
Showed some fancy footwork in stepping away from a couple of defenders on the edge of the area eight minutes in, but shot tamely at Abbiati. It kind of summed up his evening because while he offered endeavour, there was never any end product.
Held the ball up well and though he did not really get a clear sight of goal, he should have earned his side a penalty with a header that clearly struck Niang's outstretched arm.
Was given virtually nothing to do during the first half but made a few terrific stops in the second period, most notably from Jorquera at a time when 10-man Milan were under serious pressure.
M. De Sciglio
Was occasionally troubled by Antonelli but was pretty solid for the most part, and also caused problems whenever he ventured forward. Indeed, played his part in Pazzini's opener with a fine overlapping run.
Caught napping by Borriello at one point but, for the most part, he was one of Milan's more reliable performers before being forced off at the break.
Made one of several timely interventions to deny Bertolacci three minutes in and also produced a sublime piece of control and composure to create a goal for Balotelli on 60 minutes.
Caused Cassani some problems early on with his willingness to get forward and provide some width down the left-hand side, but was forced backwards the longer the half wore on. Made a fine break on 67 minutes which was crudely curtailed by Bovo, but then stupidly stuck his head in the midfielder's face, thus resulting in the most stupid of red cards.
Positioned at the base of Milan's midfield, the former Fiorentina man tried to dictate the pace and tempo of the game, but failed dismally to do so.
Struggled so badly to get into the game that it was actually easy to forget that he was playing during a listless first-half showing. However, he was a different man after the interval, making a couple of incisive runs into the area, the second of which earned the corner that led to Milan's second.
Unable to exert any influence on the proceedings. Tried to drop deep at times just to get himself on the ball, but to little or no effect.
After starting quietly, the youngster drew a spectacular save out of Frey with a fine curling effort from the right-hand side of the area. However, was then guilty of two offences - a clear handball and then a blatant push on Granqvist - which inexplicably went unpunished by the referee.
S. El Shaarawy
Starved of possession he may very well have been, but the forward was absolutely anonymous during the opening 45 minutes. Was far more lively at the start of the second half but was then replaced midway through the second half following Constant's dismissal.
Forced off midway through the first half with a suspected ankle injury picked up after being chopped down from behind by Portanova, but not before opening the scoring with a stunning strike from the edge of the area which flew in via the underside of the crossbar. In fine form at the minute so Milan will be praying he's fit to face Barca.
Came on for Granqvist for the final 15 minutes.
Sent on in place of Bovo, who was in danger of being sent off after clashing with Constant, and fared reasonably well.
Introduced early in the second period as Genoa went in search of an equaliser but did not get a clear sight of goal.
Took over at the back from the injured Mexes during the interval and slotted seamlessly into the back four.
Made an unexpectedly early entrance because of Pazzini's injury, and looked horribly rusty, picking up an immediate booking for a clumsy challenge before spending the remainder of the half giving the ball away. However, underlined his class with a composed finish on the hour after being slipped in by Zapata.