Atalanta snatched a 3-2 victory at home to AC Milan thanks to a goal in added time from substitute Luis Muriel after a double from striker Ademola Lookman in Serie A on Saturday.
Muriel struck in the 95th minute after Milan defender Davide Calabria was dismissed for a second booking two minutes earlier.
Milan remain third on 29 points, seven points adrift of leaders Juventus, who beat visiting champions Napoli 1-0 on Friday, and six behind Inter Milan. Atalanta are seventh on 23.
Lookman had opened the scoring for the hosts with a right-foot shot from a central area that deflected off Milan defender Fikayo Tomori and flew past goalkeeper Mike Maignan in the 38th.
Milan equalised just before the break with Olivier Giroud's superb header from a corner for his eighth league goal of the season.
Lookman netted his second 10 minutes after the interval with a clinical finish from Charles De Ketelaere's cross-field pass. However, Milan made it 2-2 through Luka Jovic's left-foot finish from Christian Pulisic's cross into the box in the 80th.
But in stoppage time Calabria had to leave the field after being shown a second yellow card and shortly afterwards Muriel, who came on in the 82nd minute, gave Atalanta the win.