Juventus were held 1-1 at Atalanta on Tuesday (Wednesday AEDT) for their seventh draw in their past eight league matches and 13th out of 20 Serie A games this season. However, they remain unbeaten in Serie A.
In the day's only other match, Milan fought back to win 2-1 at nearby Como.
Atalanta moved level on points with second-placed Inter Milan, who have played two matches less, and four points behind Serie A leaders Napoli.
Milan were three points below fifth-placed Juventus. The two sides face each other in Turin on Saturday, with Milan likely to be without Christian Pulisic after the US international limped off on the stroke of halftime at Como.
Juventus took the lead in Bergamo in the 54th minute following great play by Weston McKennie. The US midfielder ran on to a long ball, then played a perfectly weighted pass for Pierre Kalulu to fire past Marco Carnesecchi at the near post.
Kalulu had come incredibly close to scoring moments earlier when his header bounced off the inside of the far post and rolled across the line before Carnesecchi managed to claw it away. Television replays showed that only a few millimetres were still on the line, with about 98 per cent of the ball having gone over.
Mateo Retegui made his comeback in the 65th minute after several weeks out with injury, and the league's top scorer headed Atalanta level 13 minutes later with his 13th league goal of the season.
A historic Theo Hernandez goal saw Milan earn a comeback victory for the third time in four matches under Sergio Conceicao, who got his first Serie A win as coach.
AC Milan's Theo Hernandez opened the scoring for his side in their win over Como. (AP PHOTO)
Conceicao, who replaced the fired Paulo Fonseca at the end of last year, got his reign off to the perfect start when he steered Milan to the Italian Super Cup trophy with two comeback wins after just over a week at the helm.
That was followed by a disappointing 1-1 draw against relegation-threatened Cagliari on Saturday.
Milan again went behind on Tuesday, when Como's new signing Assane Diao - on the teenager's first start - ran down the right flank and cut inside before firing into the near bottom corner.
Hernandez had perhaps been at fault for backing off Diao too much, but he atoned for that error with a fine equaliser in the 71st minute. It was his 30th goal in Serie A, overtaking Paolo Maldini as the Milan defender with the most goals in the Italian league.
Milan turned the match around completely five minutes later when Rafael Leao ran on to Tammy Abraham's through ball and dinked it over Como goalkeeper Jean Butez.
25°C