A late goal by Paul Pogba steered Juventus to a 1-0 win at Parma in coach Antonio Conte's 100th match in charge on Saturday, while Napoli also kept the pressure on Serie A leader Roma with a 2-1 win at home to Catania.
There was more misery for AC Milan as it slipped to a 2-0 defeat at home to Fiorentina. Milan was resoundingly jeered by the fans, who also unfurled a large banner demonstrating their displeasure. Vice President Adriano Galliani left the stands after Fiorentina's second goal.
Conte rested several players ahead of Tuesday's Champions League match against Real Madrid but was forced to send on Andrea Pirlo and Fabio Quagliarella as they struggled to carve out opportunities.
Quagliarella had an immediate effect two minutes after going off the bench with a stunning long-range shot which crashed off the crossbar and into Pogba's path, allowing the young Frenchman to coolly slot into the bottom corner in the 77th minute.
Amauri had Parma's best chance with a backheeled effort which fizzed just past the left upright from close range.
Juventus and Napoli are provisionally two points behind Roma, which has won all of its matches and travels to Torino on Sunday.
Catania had not won in Naples since 1960-61 and Jose Maria Callejon gave Napoli the lead in the 15th minute with another stunning strike, curling the ball into the top corner from 20 yards.
Napoli doubled its lead five minutes later when Lorenzon Insigne rolled the ball across the outside of the penalty area for Marek Hamsik to hit first time into the top left corner.
Catania had not scored since Luigi De Canio replaced Rolando Maran as coach nearly two weeks ago, but it got back into the game in the 25th minute when Lucas Castro turned in Maxi Lopez's cross.
Next up for Napoli is Wednesday's Champions League match at home to Marseille.
In Milan, both sides had personnel problems. Fiorentina were without the injured Mario Gomez, David Pizarro and Josip Ilicic. Juan Cuadrado was suspended after video evidence was ruled inadmissable to revoke his ban following his unfair dismissal in the 2-1 defeat to Napoli.
Massimiliano Allegri was still without Matias Silvestre, Mattia De Sciglio, Daniele Bonera, Stephan El Shaarawy and Giampaolo Pazzini as well as the suspended Philippe Mexes.
Former Milan captain Massimo Ambrosini was given a warm welcome by the home fans, who displayed a banner paying tribute to his 18 years at the club. The Fiorentina midfielder was also given a standing ovation when he was substituted.
Juan Vargas broke the deadlock in the 27th minute when his free kick took a deflection off Sulley Muntari in the Milan wall to wrongfoot goalkeeper Gabriel and go into the bottom left corner.
Fiorentina all but sealed the game in the 73rd when Gabriel pushed Joaquin's cross straight at Borja Valero, who tapped it into an empty net.
Milan, which remains provisionally 10th, has to quickly pick itself back up for Wednesday's Champions League match at Barcelona.
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