Gonzalo Higuain beat Coppa Italia holders Lazio 1-0 to send Napoli through to face Roma in the semi-final.
The two-legged semi will be played on February 5 and 12, while the other clash is between Udinese and Fiorentina.
Jorginho was given his first start in a Partenopei jersey since arriving from Hellas Verona, while Pepe Reina returned from injury, but Pablo Armero, Juan Zuniga, Valon Behrami and Giandomenico Mesto missed out. Lazio were without Miroslav Klose, Stefan Radu, Ederson, Sergio Floccari and Stefano Mauri, but had still been unbeaten since Edy Reja – a former Napoli Coach – replaced Vladimir Petkovic.
Higuain had the first shot parried by Etrit Berisha at the near post, then Michael Ciani needed a perfectly-timed sliding tackle to stop the Jose Callejon pass reaching Higuain for the tap-in.
Cristian Ledesma attempted an audacious lob from the centre-circle with Reina off his line, but it was over the bar.
Callejon looked certain to score when getting on the end of a searching pass, but his second touch was surprisingly poor and allowed the defence to recover. The visitors lost Abdoulay Konko to a calf injury after just 34 minutes, making way for Pedro Luis Cavanda.
Keita was furious with Eddy Onazi when wasting a counter-attack by failing to pass it to him in a much better scoring position. At the other end, Diego Novaretti was crucial with a sliding interception to prevent Higuain netting from six yards.
A long-range Jorginho strike was comfortably smothered by Berisha, but the ex-Verona youngster went even closer with a fantastic curler from the outside left corner of the box that thumped the far upright.
Alvaro ‘Tata’ Gonzalez replaced Onazi for the second half and Higuain had penalty appeals for a mistimed Novaretti tackle, but the officials only gave a goal kick.
Callejon drilled wide and Keita was again dangerous when he burst down the left and flashed a shot across the face of goal. Ciani bravely charged down a Marek Hamsik rocket and Lorenzo Insigne’s first touch let him down in a great team move. He was substituted soon after and visibly irritated at jeers from his hometown crowd.
Jorginho should’ve done better on 78 minutes when he side-footed over the bar after a poor Berisha punch on the low Dries Mertens cross.
Napoli were pushing and broke through eventually. Cristian Maggio started the move, then Callejon’s shot was going wide before Higuain flicked it in at the back post. Lazio demanded an offside flag, but replays showed he was in a valid position for his third goal against the Biancocelesti this season, as Pipita bagged a brace in a 4-2 Serie A victory last month.
Napoli 1-0 Lazio
Scorers: Higuain 82 (N)
Napoli: Reina; Maggio, Fernandez, Albiol, Reveillere; Jorginho (Dzemaili 91), Inler; Insigne (Mertens 69), Hamsik (Pandev 76), Callejon; Higuain
Lazio: Berisha; Ciani, Novaretti, Dias (Biava 72); Konko (Cavanda 34), Onazi (Gonzalez 46), Ledesma, Lulic; Anderson, Keita; Perea