Juventus was held to a costly 1-1 draw at Bologna on Wednesday, potentially giving AC Milan a decisive advantage in the race for the Serie A title.
Bologna's 35-year-old captain Marco Di Vaio put the hosts ahead in the 17th minute and Mirko Vucinic equalized for Juve in the 58th.
The match was postponed from last month due to a snowstorm and now Milan leads Juve by two points with both clubs having played the same number of matches.
Making matters worse for Juve was that defender Leonardo Bonucci was expelled in the 84th, leaving the Turin side without its three top center backs for a visit to Genoa on Sunday.
Juventus' first-year coach Antonio Conte was also sent off, for protests in the 72nd.
Juventus was without its two most trusted defenders, with Giorgio Chiellini and Andrea Barzagli each out injured, setting up an unusual pairing of Bonucci and Martin Caceres in front of goalkeeper Gianluigi Buffon.
Still, Juventus started well and a free kick from Andrea Pirlo nearly deflected in off Bologna's wall in the 12th.
However, Di Vaio then beat Juve's offside trap and collected a through ball from Gaston Ramirez before slotting a shot past Buffon for his ninth score of the season.
Juventus didn't reorganize itself until midway through the second half, when Vucinic beat the offside trap and found the target with a lob shot from beyond the area. Having transferred from Roma, Vucinic had a strong start to the season but had struggled lately and this was just his fourth goal of the campaign.
In the 64th, Stephan Lichtsteiner and Claudio Marchisio had successive chances denied by Bologna's in-form goalkeeper Francois Gillet.
Then, after Conte was sent off for protesting a perceived missed foul on Lichtsteiner, Bonucci picked up his second yellow for a foul on Ramirez.
