Zlatan Ibrahimovic made an emphatic return to the AC Milan side as the Rossoneri moved three points clear with a 4-0 win over Palermo, as Juventus slipped up.
The Sweden international scored a 14-minute hat-trick on his return after a three-game suspension as the Rossoneri cruised to victory in Sicily, showing ominous form ahead of their UEFA Champions League second leg against Arsenal.
Thiago Silva added a fourth goal as Milan put the ball back in second-placed Juventus' court in the race for the Scudetto.
For Palermo, coach Bortolo Mutti is now set for an uncomfortable debrief with the club's president Maurizio Zamparini.
Juventus stumbled in response, being held to a 1-1 draw at home to Chievo on Saturday evening.
Paolo De Ceglie put the Bianconeri in front in the 18th minute, but they failed to build on their lead and were punished when Boukary Drame levelled for Chievo in the 76th minute.
The draw leaves Juve three points behind Milan with a game in hand, one which must now be won if Antonio Conte's side want to return to the Serie A summit next Wednesday.