A late Mirko Vucinic double gave Roma a 2-0 home win over Bologna to send the Coppa Italia holders into the quarter-finals, while Torino defied their poor league form with a 1-0 victory at Fiorentina.
Montenegro forward Vucinic, a second-half substitute, scored from close range after 83 minutes and capitalised on a blunder by Marcello Castellini to steal possession, race on to goal and seal it three minutes later.
With captain Francesco Totti resting on the bench, the hosts had struggled to get going in their first appearance in this season's cup until the arrival of Vucinic, who also hit the crossbar with a header and failed to convert two good chances.
Roma, who have now won eight consecutive games in all competitions, will meet the winner of the tie between Serie A leaders Inter and Genoa, which takes place on January 13, in the next round.
Rolando Bianchi fired home a Tommaso Vailatti cross after 19 minutes to give Torino coach Walter Novellino his first victory since replacing Gianni De Biasi last week.
Fiorentina came close to equalising on several occasions and defender Manuel Pasqual headed over with the goal gaping at the end of the first half but its Torino who will meet Lazio in January's quarter-finals.
Napoli, Udinese and Sampdoria are already through to the last eight after winning their last-16 ties, which have been spread over three months because of European fixture clashes.
Juventus complete the round with a home tie against Catania on January 14, the winners meeting Napoli.
Round 5 Results
Wednesday 12 November
Udinese 0-0 Reggina AET (Pens: 8-7)
Sampdoria 2-1 Empoli
Napoli 3-1 Salernitana
Wednesday 3 December
Milan 1-2 Lazio AET
Wednesday 17 December
Fiorentina 0-1 Torino
Roma 2-0 Bologna
Round 5 Fixtures
Tuesday 13 January
Inter v Genoa (2000)
Wednesday 14 January
Juventus v Catania (1945)
Wednesday 21 January, 4 February
Inter/Genoa v Roma
Lazio v Torino
Napoli v Juventus/Catania
Sampdoria v Udinese
[Coppa Italia 2008-09 Draw]
Coppa Italia Fifth Round Review:
[Wednesday 12 November] – [Wednesday 3 December] – [Wednesday 17 December] - [Tuesday 13 January] - [Wednesday 14 January]
Source: Reuters / Lega Calcio