Giampoalo Pazzini scored the opening goal but was among two AC Milan players injured in Friday night's 2-0 win at Genoa, just four days before the Italian power's Champions League match at Barcelona.
Pazzini was limping from a bruise below his left knee when he scored in the 22nd minute, and he was replaced two minutes later by Mario Balotelli. Defender Philippe Mexes came off at the start of the second half, and Balotelli doubled the lead in the 60th with his fifth goal in five games since joining Milan from Manchester City.
Milan's Kevin Constant was ejected in the 65th for arguing when he received his second yellow card of the game.
Milan takes a 2-0 lead to Spain for its second-round, second-leg match. Milan (15-7-6) moved within two points of second-place Napoli (15-3-8) in the Italian league.
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