Two classy first-half goals gave Juventus a 2-1 win at Chievo on Sunday, restoring their three-point lead at the top of Serie A as Lazio and Inter Milan lost touch after defeats by lowly opponents.
Alessandro Matri volleyed home after 10 minutes and Switzerland midfielder Stephan Lichtsteiner finished a well-worked move three minutes before halftime for Juventus whose new signing Nicolas Anelka was left on the bench.
Genoa's Marco Rigoni headed in from a corner in the fifth minute of stoppage-time to give them a 3-2 win over third-placed Lazio, who slumped to their second successive league defeat despite coming back from two goals behind.
Marco Borriello and Andrea Bertolacci struck in a six-minute spell in the first half to put Genoa in control before Sergio Floccari pulled one back and Stefano Mauri levelled with an 82nd-minute penalty.
Inter produced a dire performance in a 3-1 loss at table-propping Siena which left coach Andrea Stramaccioni fuming.
"It was an ugly defeat and an ugly performance and there is no justification for it," he told RAI television.
"We've got to find ourselves again, as we are still the team who in November were a point off the leaders and had great ambition."
There were three goals in a four-minute first-half spell as Siena's debutant Innocent Emeghara tapped in from close range, Antonio Cassano levelled almost immediately and Alessio Sestu put the hosts back in front with a long-range effort.
Siena wrapped things up 10 minutes after the re-start, Inter's Cristian Chivu hauled down Emeghara, was sent off and Alessandro Rossina converted the penalty.
Champions Juventus restored their three-point lead after Napoli had briefly pulled level with a 2-0 win over Catania on Saturday. Juve have 52 points from 23 games, Napoli 49, Lazio 43 and Inter are fourth with 40.
Siena's win took them off the bottom of the table on goal difference from Palermo who lost 2-1 at home to Atalanta, despite fielding four new signings.
Both teams have 17 points, three adrift of Pescara who twice led but lost 3-2 at home to Bologna in a game of three penalties.
Vladimir Weiss won and converted the first for Pescara on the half hour mark Alessandro Diamanti replied four minutes later with another spot-kick and the third was converted by Gaetano D'Agostino for the hosts on the stroke of halftime with Weiss injured.
Second-half goals from Alberto Gilardino and Panagiotis Kone sent Pescara to a fourth straight defeat.
Juventus, who had won only once in their previous four league games and were knocked out of the Italian Cup by Lazio in midweek, went ahead when Arturo Vidal sent a diagonal chip into the path of Matri who volleyed into the far corner.
Right wing-back Lichtsteiner popped up on the left of the penalty area to provide an emphatic finish after Matri rolled the ball to Sebastian Giovinco who teed up the Swiss with a clever backheel.
Cyril Thereau pulled one back for the Flying Donkeys early in the second half but Juventus, with coach Antonio Conte barred from the touchline for his furious outburst over the refereeing against Genoa last week, held out comfortably.
"It is very motivating to know you cannot afford to get anything wrong," said Juventus goalkeeper Gianluigi Buffon.
"There are 15 games to go and everything is still up for grabs. I am glad to have more title rivals."