Mario Balotelli scored his fifth goal in five Serie A games for Milan as they survived a second-half red card to Kevin Constant to defeat Genoa 2-0 at Stadio Luigi Ferraris.
Giampaolo Pazzini opened the scoring for the Rossoneri in rather unconventional fashion. Nursing an injury following a poor challenge minutes before, the striker stopped hobbling long enough to lash a wonderful effort in off the underside of the bar on 20 minutes and was promptly substituted.
Balotelli was his replacement, and the January signing from Manchester City continued his fine run of form since returning to Italy with a well-taken goal after 60 minutes as he punished some slack defending from a corner.
Milan lost Constant to a red card - the left-back reacting angrily to a poor challenge from Cesare Bovo to earn his second booking of the night - but held on despite some late pressure to move to within two points of second-placed Napoli ahead of their Champions League trip to Barcelona in midweek.
Genoa, meanwhile, remain five points clear of danger having played a game more than the three teams below them in the table.
Pazzini sustained his injury after 18 minutes when Daniele Portanova clattered into him from behind, jarring his trailing leg, and was still hobbling gingerly around when he struck a superb opener for Milan four minutes later.
M'baye Niang had already gone close with one thunderous drive from the right and Milan attacked from that flank again as Portanova produced a poor attempted clearance from a Mattia De Sciglio cross. The ball squirted out to Pazzini, who with one operational leg unleashed a thumping drive from 15 yards which caught the underside of the bar before pounding into the turf and in.
Pazzini was soon replaced by Balotelli, who was in the book within 20 seconds for a push on Andrea Bertolacci and was then left feeling his shins after a collision. Robinho started warming up for Milan but Massimiliano Allegri was not pressed into a second change as Balotelli jogged it off.
Still, it was an underwhelming performance from a Milan side unbeaten in nine and they were hugely fortunate not to see Genoa win at least one spot-kick in a first half that witnessed plenty of action in the away penalty box.
A lack of intent on the part of Christian Zapata allowed to Milan escape when the defender handled the ball, but Niang was surely guilty of the offence later when Marco Borriello headed back across goal from a Bovo cross and the forward blocked his effort with a raised arm.
Genoa were furious, doubly so on 39 minutes when Niang clearly pushed Andreas Granqvist as a Daniel Tozser free-kick came into the box but again went punished as Milan took a somewhat undeserved 1-0 lead into the break.
The Rossoneri were again the beneficiaries of fortune soon after the break when Bovo struck a tremendous 30-yard free-kick that curled wickedly at high speed and cannoned against the post.
Borriello and Bertolacci wasted further chances from inside the Milan box before the visitors started to apply more pressure, with Mathieu Flamini prominent as he earned a booking for diving after knocking the ball past Sebastien Frey and then won a corner with a clever run and low shot that Frey tipped round the post.
From the resulting corner, Balotelli made it 2-0. Genoa's defence started to inch forward after the ball came in but Milan caught them out round the back, Zapata slipping in a quick pass for Balotelli who produced an emphatic finish, across Frey and inside the far post.
Milan were in firm control but their supremacy was threatened when Constant saw red. Bovo caught the left-back with a poor challenge, earning a booking in the process, but Constant's furious reaction saw him shown his second caution of the night.
Genoa took heart as Luca Antonelli and Granqvist both threatened, with the latter having another, if more tenuous, penalty appeal turned down. But Milan were resolute in defence, holding on for a 2-0 win that sends them into Tuesday's Champions League showdown with Barcelona in good heart.