A last-gasp goal by Brazilian striker Amauri gave Juventus a 2-1 win at Lecce on Sunday while injury-ravaged AC Milan beat Catania 1-0 at the San Siro thanks to a Kaka goal.
Amauri nodded home in the 90th minute after Lecce's Daniele Cacia had cancelled out a fine 57th-minute free kick by Sebastian Giovinco.
Kaka's 65th-minute header from a corner, which took a touch from Catania defender Lorenzo Stovini on the way into the net, was enough to end Milan's four-match winless run in all competitions.
Second-placed Milan and third-placed Juventus, who meet in Turin next weekend, both have 30 points from 15 games, six behind champions Inter Milan, who won 3-0 at Lazio on Saturday.
Juve had plenty of possession in the first half but posed little threat to the tidy hosts.
They looked more dangerous after the break when Italy under-21 forward Giovinco, standing in for injured captain Alessandro Del Piero, drove into the top corner to score his first goal in Serie A with Juventus.
Lecce responded well to falling behind and Jose Castillo wasted a great chance before Cacia levelled with a delightful volley.
But Amauri's goal meant it was all to no avail for the southern side, who have not won a league match since September.
Milan made a bright start at the San Siro despite being without a host of injured regulars, including forwards Ronaldinho and Marco Borriello and midfielders Clarence Seedorf, Andrea Pirlo and Massimo Ambrosini.
Andriy Shevchenko, Paolo Maldini and Emerson all came close early on and Kaka had a shot pushed onto the post shortly after Catania forward Giuseppe Mascara had hit the woodwork at the other end.
Milan suffered after taking the lead in the second half. Mascara had a header well saved in the closing stages, when the visitors also had a penalty shout for handball by Kakha Kaladze denied.
Fourth-placed Napoli beat Siena 2-0 at home thanks a second-half blitz that produced goals by Christian Maggio and Argentine striker German Denis.
Fiorentina thrashed struggling Torino 4-1 to consolidate fifth place with the help of a brace by Italy forward Alberto Gilardino, who joins Genoa's Diego Milito at the top of the Serie A scorer standings with 11 goals.
The home defeat leaves Torino boss Gianni De Biasi in grave danger of losing his job