Inter Milan suffered another wobble in their bid to reclaim the Serie A title after Saturday's 1-1 draw with Atalanta, who bounced back from Champions League humiliation against Bayern Munich.
Nikola Krstovic earned a point for Atalanta by scoring in the 82nd minute at the San Siro, cancelling out Pio Esposito's angled drive after 26 minutes for the hosts who had looked to be extending their league lead to 10 points.
But Inter coach Cristian Chivu and his players were livid at Krstovic's goal being awarded after what they saw as a push on Denzel Dumfries by Kamaldeen Sulemana, whose saved shot led to the leveller.
Chivu was sent off for his vehement protests against the officials in a heated end to what had up to that point been a humdrum affair in soaking wet Milan.
Dumfries held his head in his hands when referee Gianluca Manganiello pointed to the centre circle to give the goal, which handed AC Milan the chance to move to within five points of their local rivals.
Home fans were again outraged moments later when Davide Frattesi went down looking for a penalty under a challenge from Giorgio Scalvini, who tapped his Italy teammate's foot and was cleared of committing a foul.
No one from Inter spoke to media after the game in protest at the decisions.
Milan, who prevailed in their local derby with Inter last weekend, travel to Rome to take on Lazio on Sunday night and can reignite a title race which looked as good as over a week ago.
A fighting point for Atalanta came after Tuesday's humiliating 6-1 defeat by Bayern in the Champions League, a competition for which they are just about in contention to qualify for this season.
Atalanta, who have to face Bayern in Munich on Wednesday, are four points behind Como and Roma, who are separated by goal difference in fourth and fifth and face off on Sunday.
"I really liked the reaction of the team, it's very easy to still be affected as it was only four days ago that we played Bayern," said Atalanta coach Raffaele Palladino.
"But the team played like men, like the good players that they are."
MCTOMINAY BACK
Juventus, a point behind Roma and Como, can move into the top four with a win at Udinese in Saturday's late match.
Reigning champions Napoli trail Inter by nine points in third place after coming from behind to beat Lecce 2-1 in Naples, where Scott McTominay made his return from injury.
Rasmus Hojlund and Matteo Politano's goals overturned Jamil Siebert's surprise early opener for Lecce as Napoli consolidated their top-four position, eight points above Roma and Como.
More good news for coach Antonio Conte, who has had to deal with a raft of injury problems all season, came in the shape of McTominay, who made his first appearance in over a month as a half-time substitute.
Scotland midfielder McTominay has become a huge fan favourite at Napoli since arriving from Manchester United, and his return came as Kevin De Bruyne and Andre-Frank Anguissa continued their comebacks from injury.
De Bruyne replaced Anguissa at the break and looked in decent nick in his second appearance since tearing his hamstring while scoring a penalty against Inter in October.
There was a worrying moment late on when Lecce attacker Lameck Banda had to be rushed from the field with the Stadio Diego Armando Maradona in hushed silence after he fell to the turf.
Broadcaster DAZN reported that he was receiving treatment in an ambulance and was conscious after a fall, which was reminiscent of Edoardo Bove's on-pitch heart attack while playing for Fiorentina last season.