Adrien Rabiot won the penalty that brought AC Milan level and then scored twice as the Rossoneri came from behind to beat Como 3-1, cutting Inter Milan's lead at the top of Serie A back to three points.
Inter had moved six points clear of Milan and Napoli after beating Lecce 1-0, while Napoli were held by Parma. Milan's response kept Massimiliano Allegri's side within reach after a difficult start against an in-form Como team.
Como had the better of the opening spell, and Milan needed a late first-half break to get back into the match. Rabiot was brought down by Kempf, and Christopher Nkunku converted the penalty, with the ball slipping under Jean Butez.
The equalizer changed the shape of the match. Milan went ahead 10 minutes into the second half after Rafael Leão controlled a crossfield pass, came inside and lifted the ball toward Rabiot, who chested it down before volleying across goal into the bottom right corner.
Rabiot finished the comeback shortly before full time. Niclas Füllkrug headed the ball back into the path of the France midfielder, who drove a low shot into the near corner to make the result safe for Milan.
The win was important for the Rossoneri because Inter's victory over Lecce and Napoli's draw with Parma had briefly widened the title gap. Milan did not allow that six-point margin to last.
Elsewhere in Serie A, Bologna ended a poor run by fighting back to beat relegation-threatened Hellas Verona 3-2 in a match that included several standout finishes.
Hellas Verona struck first after Bologna lost the ball in the opposition penalty area. Antoine Bernède carried play almost from box to box before setting up Gift Orban, who finished the move.
Riccardo Orsolini curled in Bologna's equalizer from a clever free kick routine, and Bologna then moved ahead through impressive goals from Jens Odgaard and Santiago Castro before halftime.
Hellas Verona got one back in the 71st minute when Bologna midfielder Remo Marco Freuler accidentally turned a cross into his own net, but Bologna held on for a 3-2 win after having gone without a victory since November.