Ten-man Lazio have beaten AC Milan for the second time in three days to reach the last four of the Coppa Italia.
Having seen off the Rossonieri 3-1 at home in Serie A on Sunday, Lazio were victorious thanks to Lucas Biglia's penalty, and held on despite having Lorik Cana sent off late in the first half.
The visitors should have been in front after eight minutes, when Miroslav Klose 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 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.
Lazio's defence issues were deepened in the second half, when Mauricio went off injured, replaced by Dusan Basta. Milan responded by introducing Keisuke Honda from the subs' bench and going more direct in their play.
They thought that they had an equaliser on 68 minutes when Pazzini found the top corner with a volley, but it was chalked off for handball in his control.
The hosts took total control in the final quarter of an hour, pinning Lazio into their back third, but struggled to break through. Lazio were still dangerous on the counter, with Keita striking the post with a vicious low drive on 77 minutes.
Milan manager Filippo Inzaghi threw on new signing Suso in the final 10 minutes, but despite having 60% possession, they could not prevent Lazio making the last four.
Cerci thought that he had rescued extra time, but his clipped effort in the 92nd minute was ruled out for offside.
