Mario Balotelli deviated slightly from the script in scoring twice on his AC Milan debut in a 2-1 victory over Udinese, but his winner arrived in typically controversial fashion.
Balotelli was supposed to be on the bench for his first game back in Italy, but with Giampaolo Pazzini injured in the warm-up the former Manchester City striker had an unexpected late call-up into the starting line-up. And after just 35 seconds he struck the post.
All eyes were on the mercurial Italy striker following his £19 million return to Italy and it took him only 24 minutes to open his account in Rossonero colours, hooking Stephan El Shaarawy's pullback from the by-line underneath Padelli and into the back of the net.
Udinese made the most of the hysteria to spring a surprise at the San Siro in the second half, Gianpiero Pinzi souring the party atmosphere with a modest goal on the counter-attack.
El Shaarawy won a suspicious penalty from Thomas Heurtaux and Balotelli snatched up the ball with glee and fired home the winner in the 94th minute.
Juventus went three points clear at the top of the Serie A table with a 2-1 win away at Chievo on Sunday, thanks to goals from Alessandro Matri and Stephan Lichtsteiner.
An early strike by Alessandro Matri was followed by a second just before the break from Stephan Lichtsteiner, putting the visitors in control before Cyril Thereau reduced the arrears early in the second half.
Thereau had a chance to level the scores shortly after, but in truth it was a victory the league leaders deserved with Antonio Conte's side missing chances to extend their lead late on.
Siena climbed off the bottom with a shock 3-1 home victory over Inter Milan, who have now failed to win on the road since November.
Home debutant Innocent Emeghara, signed from Lorient, stunned the Nerazzurri with his first Siena goal only for Antonio Cassano to equalise inside 60 seconds.
It was a false dawn for Inter, though, as an Alessio Sestu goal ensured Giuseppe Iachini's men led their illustrious guests going into the break. The second half might have been a different story for Inter had Cristian Chivu not seen red for a professional foul, with Alessandro Rosina converting the resulting penalty to settle the tie.
A last-gasp goal from debutant Marco Rigoni secured Genoa's dramatic 3-2 victory over Lazio, lifting them out of the relegation zone.
It was a well-deserved first win for new head coach Davide Ballardini, whose side built a two-goal lead inside 21 minutes thanks to goals from Marco Borriello and Andrea Bertolacci.
But the hosts would have to fight to the very end for the three points as Sergio Floccari and Stefano Mauri dragged Lazio back into the game, only for deadline-day signing Rigoni to net with a bullet header in the fifth minute of injury time.
Fiorentina got back to winning ways with a comfortable 2-0 victory over Parma at the Stadio Artemio Franchi.
Vincenzo Montella's men were chasing a first win in five games to restore their bid for a Champions League place and veteran striker Luca Toni put them on track with his ninth Serie A goal against Parma. And the visitors, who are sliding down the league table, were condemned to a second straight defeat when Stevan Jovetic scored five minutes into the second half.
Palermo's rash of January transfer window signings were unable to change their fortunes as they lost 2-1 at home to fellow strugglers Atalanta.
Palermo signed a total of 10 players in January, with Diego Fabbrini and Alejandro Faurlin the last to arrive on deadline day. They both made their debuts but ended in a losing cause as second-half goals from Carlos Carmona and German Denis put Atalanta in control before Nelson's late consolation for the hosts.
Pescara dropped into the relegation zone after losing 3-2 at home to Bologna in an eventful contest featuring three penalties in the space of 16 first-half minutes.
The home side twice took the lead from the spot through Vladimir Weiss and Gaetano D'Agostino, with Alessandro Diamanti initially equalising with a penalty for the visitors. Diamanti then set up a second equaliser for Alberto Gilardino before Panagiotis Kone scored what proved to be the winner midway through the second half.
The win lifted Bologna up to 14th, five points clear of the drop zone into which Pescara slipped due to Genoa's 3-2 win over Lazio.