Inter won 3-2 at Juventus in an enthralling encounter to triumph 5-4 on aggregate and reach the Coppa Italia semi-finals. Elsewhere, Lazio earned a surprise 2-1 win away at Fiorentina and Catania squeezed past Udinese on the away goals rule to complete the last four line-up.
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 in the opening 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 the Nerazzurri were level again when Julio Cruz converted a penalty after Hasan Salihamidzic had been 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 late on for a crude hack on former team mate Patrick Vieira.
The Serie A leaders will now face Lazio in the semi-finals after the Rome side belied their poor league form to beat Fiorentina 2-1 in Florence and secure a 4-2 aggregate victory.
The once-powerful capital club, three points above the relegation zone, went behind to Franco Semioli's strike off the near post in the 17th minute 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 Coppa semi-final earlier 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.
Catania looked on their way out after missing a host of chances in the afternoon kick-off before the Japanese forward turned in Juan Manuel Vargas's excellent low cross.
The visitors, coached by former Catania coach Pasquale Marino, took the lead in the first minute when Simone Pepe bundled in a corner but Gionatha Spinesi equalised from the spot on half time 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.