MILAN, Jan 30 (Reuters) - Serie A leaders Inter Milan won 3-2 at Juventus in an enthralling encounter on Wednesday to triumph 5-4 on aggregate and reach the Italian Cup semi-finals.Inter will face Lazio in the last four after the Rome side beat Fiorentina 2-1 away earlier to record a 4-2 aggregate victory. Catania set up a meeting with holders AS Roma by beating Udinese on away goals. Inter's commitment to the competition has been questioned but they were certainly motivated against their bitter rivals, even though former Juve striker Zlatan Ibrahimovic was rested. Reserve forward Mario Balotelli opened the scoring for the visitors on 10 minutes before Alessandro Del Piero hit back with a free kick in an exhilarating first half. Vincenzo Iaquinta put Juve in front when he nodded in after debutant Guglielmo Stendardo had hit the post with a header but Inter were level again when Julio Cruz converted a penalty after Hasan Salihamidzic had been harshly penalised for handball. Balotelli grabbed the winner with a superb finish nine minutes into the second half. Juve pushed for an equaliser but their hopes ended when Mauro Camoranesi was sent off on 85 minutes for a crude hack on former team mate Patrick Vieira. Lazio, three points above the Serie A drop zone, went behind to Franco Semioli's strike off the near post on 17 minutes before pulling level when a free kick from Aleksandar Kolarov evaded everyone and nestled in the corner. Substitute Tommaso Rocchi then scored only minutes after replacing Rolando Bianchi when he chested down strike partner Goran Pandev's superb pass and fired home from close range. Catania progressed to their first Italian Cup semi-final with Takayuki Morimoto's 89th-minute strike securing a 2-1 home win over Udinese, which put the Sicilians through on away goals after a 4-4 aggregate score. The visitors, coached by former Catania boss Pasquale Marino, took the lead in the first minute when Simone Pepe bundled in a corner but Gionatha Spinesi equalised from the spot on halftime after Damiano Ferronetti fouled Giuseppe Mascara. Catania will play Roma in a two-legged semi-final in April and May after the holders beat Sampdoria 2-1 on aggregate in their quarter-final following Tuesday's 1-0 second leg win.