Lazio lead AC Milan 1-0 at San Siro after the first half of their Coppa Italia quarter-final, although they will have to hold on with 10 men after having Lorik Cana sent off for two bookable offences late in the first period.
The visitors should have been in front after eight minutes, when Miroslav Klose - who scored when Lazio beat Milan 3-1 in the league three days prior - rounded keeper Christian Abbiati after intercepting a poor back-pass for Ignazio Abate, but missed the target.
Two minutes later, Abate was sloppy in his back-pass once more, but was again let off when it was not capitalised on.
Milan did have chances - Jeremy Menez volleyed straight at Etrit Berisha on 17 minutes - but it was Lazio who took charge, closing out Milan's lone striker Giampaolo Pazzini, leaving him isolated.
Milan conjured up an effort on 32 minutes, when Michelangelo Albertazzi's early cross was brought down by Pazzini, who found rare space and fed Alessio Cerci, but Berisha was equal to the volleyed effort.
Aquile finally got their breakthrough when a Danilo Cataldi free kick was deemed to have struck Albertazzi on the hand, and Lucas Biglia made no mistake, slotting calmly down the left while Abbiati plunged right.
Lazio's task was hardened when Cana picked up two yellows in five minutes, to give AC Milan real hope of a comeback.
