Juventus' Serie A title chances were given an unexpected boost on Sunday when Atalanta stunned Inter Milan 3-1 to dominate the derby game in Bergamo.
Antonio Conte's champions had brushed off the threat of Pescara on Saturday, with a 6-1 away rout, which restored the Turin giants' four-point lead over Inter.
With Atalanta lingering around mid-table, Inter were expected to return from nearby Bergamo with at least a share of the points.
However, a week after humbling Juventus 3-1 in Turin to come within a point of the lead, Andrea Stramaccioni's side saw their gap back at four points as Atalanta turned on the class at the Atleti Azzurri d'Italia stadium to move up to sixth.
Earlier on Sunday, stuttering Lazio relaunched their campaign by dominating Roma 3-1 in a rain-lashed Rome derby as high-flying Fiorentina piled the pressure on AC Milan and Napoli fought back to beat Genoa 4-2.
Trailing 2-1 after Antonio Candreva and Miroslav Klose struck for Lazio to cancel out Erik Lamela's opener, Roma were stung minutes into the second half when Daniele De Rossi was given a straight red card for a slap to the face of Stefano Mauri as the pair tussled in the area.
Mauri doubled Roma's agony when he pounced on a defensive mistake to put Lazio 3-1 up.
Roma fought back and reduced the arrears in spectacular style when Miralem Pjanic hit a long-range free-kick in the 90th minute which beat retreating keeper Marchetti - but it proved too little too late.
Roma coach Zdenek Zeman suggested the rain had helped Lazio's long-ball game.
"We did well in the first 20 minutes, in fact until the pitch was still good for playing football," said Zeman. "Then we were less effective because we can't play long balls upfield the same way our opponents do."
Lazio coach Vladimir Petkovic said: "There was no question over our commitment to win. It was a job done by the whole team, which was able to play our preferred long ball game."
Napoli, meanwhile, cemented third spot after a valiant fight back from Ciro Immobile's 23rd-minute opener for Genoa took them to a 4-2 win.
Fiorentina maintained their purple patch with a 3-1 victory over AC Milan at the San Siro.