Giampaolo Pazzini's 13th league goal of the season proved to be unlucky for Genoa, as he and Mario Balotelli struck in either half to condemn the Grifone to a second consecutive defeat. Milan were reduced to ten men halfway through the second half after Kevin Constant was sent off for a second yellow card. Massimiliano Allegri can now turn his attention to Tuesday night's last 16 Champions League tie at Barcelona, where the Rossoneri will defend a 2-0 first leg lead.
Constant and Marco Borriello both faced their former clubs, while M'Baye Niang was given a chance to shine with Balotelli still not fully match fit, following a shin injury.
Heavy rain throughout the week meant Genoa were forced to train solely in the gym. They struggled to connect many of their early passes as the ball zipped around the soggy pitch.
Borriello had an early penalty shout turned down after tumbling over Cristian Zapata in the box. Daniele Portanova was then cautioned for a scathing challenge to the back of Pazzini's leg. The frontman briefly went off for treatment and could be seen limping heavily upon returning to the field.
Niang stung Sebastien Frey's palms with a vicious drive before the visitors opened the scoring midway through the first half. Mattia De Sciglio's low cross was poorly cleared by Portanova into the path of the peg-legged Pazzini, who fired the ball in off the bar. The frontman succumbed to his injury and was replaced by Balotelli, who was instantly booked for a silly foul on Juan Vargas.
Genoa had three more penalty appeals turned down in quick succession. Zapata's palm in the box was ruled accidental, before Niang's handling of Daniel Toszer's header from the byline went unpunished. Niang played with fire once more, pushing Andreas Granqvist over as a free kick was played into the box. Borriello met the ball and swept a half volley over the bar.
Mario Yepes replaced Philippe Mexes at the break as the Frenchman went off as a precautionary method ahead of Tuesday's game. The home side almost equalised five minutes after the restart. Cesare Bovo bent a superb free kick over the Milan wall and against the post, leaving Christian Abbiati stranded. Minutes later, Balotelli found space on the edge of the box. With teammates pouring forward in support, the striker opted to go down the selfish route and fired over the bar.
Mathieu Flamini took a poor touch as he tried to round Frey and went to ground. The midfielder was cautioned for simulation. Flamini almost redeemed himself when he squeezed past two defenders and was denied by a superb fingertip save from Frey, who somehow turned the ball past the post. From the resulting corner, Genoa failed to clear the ball, Zapata slipped in Balotelli and the forward buried a shot into the far corner.
Genoa were handed a lifeline when Milan were reduced to ten men. Bovo was booked for a late challenge on Constant, who didn't take too kindly to the tackle and tussled with the Grifone defender. The pair were cautioned and both sets of players had to intervene, with Flamini eventually escorting an irate Constant off the pitch.
Davide Ballardini went all out to try and get something from the game. Portanova almost reduced the arrears, but his header from a corner was straight at Abbiati. Niang could have sealed the game for the Rossoneri, but his hesitancy caused him to sidefoot a shot into Frey when the better option was to use power. Abbiati denied Cristobal Jorquera from 25 yards, before Bosko Jankovic fired wide after ignoring an unhappy Borriello in space.
Milan's defensive line absorbed all that the Genoa attack could throw at them to preserve their two goal margin. They'll have to do exactly the same thing at the Nou Camp on Tuesday night.
Genoa: Frey; Granqvist, (Jankovic 77) Portanova, Moretti; Cassani, (Immobile 59) Bovo, (Jorquera 69) Tozser, Vargas, Antonelli; Bertolacci; Borriello
AC Milan: Abbiati; De Sciglio, Mexes, (Yepes 46) Zapata, Constant; Flamini, Montolivo, Muntari; Niang, Pazzini, (Balotelli 25) El Shaarawy (Abate 68)
Goals: Pazzini 22 (M), Balotelli 60 (M)
Sent off: Constant 65 (M)