Roma's mini-stumble continued as a goal four minutes into injury time by Domenico Berardi saw struggling Sassuolo claim a 1-1 draw with the Serie A leaders at the Stadio Olimpico, while champions Juventus cruised past Napoli with a 3-0 win.
Juve ominously moved to within a point of Roma following goals from Fernando Llorente, Andrea Pirlo and Paul Pogba.
Only the late dismissal of Angelo Ogbonna soured an otherwise memorable day for Antonio Conte's side, who have now won eight of their past nine league games.
Rudi Garcia's side had seen their perfect run come to an end last weekend with a draw at Torino, but Sunday's game against lowly visitors appeared to offer a great chance to return to winning ways.
An own goal by Alessandro Longhi after 19 minutes put the hosts ahead and they were completely dominant, but they failed to capitalise and were made to pay in injury time as they conceded for only the third time this season.
AC Milan's worst start to a season since 1981 continued as they were held to a 0-0 draw at Chievo, further increasing the pressure on coach Massimiliano Allegri. It could have been even worse for the Rossoneri as Chievo saw a goal disallowed for offside midway through the second half, although Robinho hit the post on a frustrating afternoon for Milan at the Stadio Marc'Antonio Bentegodi. Both sides ended the game with ten men, Riccardo Montolivo followed down the tunnel by Sergio Pellissier towards the end of the match.
Balde Keita made his entrance into Serie A with an inspiring performance and a goal -- although it was not enough for Lazio to take all three points as they recorded a 1-1 draw at Parma. The 18-year-old gave the Biancoceleste the lead early in the second half after tearing the Parma defence apart in the first 45 minutes, but an equaliser from Alessandro Lucarelli soon afterwards earned the home team a point, although that may not be enough for Lazio's under-pressure coach Vladimir Petkovic.
Genoa picked up their fourth win from the six games since Gian Piero Gasperini took over as coach with a 2-0 success over Hellas Verona. The Rossoblu's third win in a row, secured by goals from Daniele Portanova and Juraj Kucka in the first half, lifted them to within five points of their opponents and into a much healthier position than the one they found themselves in when Gasperini took charge.
A late goal from Daniele Conti saw Cagliari snatch a 2-1 win at home to Torino and end a run of three successive defeats in Serie A. Midfielder Conti had also given the hosts a first-half lead, but a draw seemed the most likely result following Ciro Immobile's equaliser -- until Conti struck again two minutes from time. It was only the second win in 11 matches for Cagliari but lifts them above Torino, who remain without a victory since September 22.
Marko Livaja grabbed a late winner as Atalanta saw off the challenge of Bologna at the Stadio Atleti Azzurri d'Italia. The Croatian scored with practically the last kick of the game to seal a 2-1 win for Stefano Colantuono's men after Davide Brivio's goal had been wiped out by Rolando Bianchi. The win lifts them three points clear of AC Milan in mid-table and leaves Bologna just a point above the drop zone.