After being held to a 1-1 draw at relegation-threatened Udinese in a rearranged match on Wednesday, Atalanta missed the opportunity to go third in Serie A.
By scoring in the opening minute, Udinese shocked Atalanta, but Luis Muriel canceled the objective of Roberto Pereyra on the halftime stroke.
Atalanta stayed sixth, a point below the top four and 10 behind AC Milan, the leader of the table. Four points above the relegation zone, Udinese is now.
In the Italian Super Cup, Juventus and Napoli play later, with Bianconeri coach Andrea Pirlo under increasing pressure.
Originally, the match in Udine was scheduled for December 6, but the ground was waterlogged.
Udinese, who had lost four of his previous five games, got off to a great start when Pereyra cut in from the right and, after 23 seconds, put an angled drive between the legs of keeper Pierluigi Gollini to give his side the lead.
Ownership was dominated by Atalanta, but it was Udinese that looked the more dangerous. However, when Muriel collected the ball just outside the area and beat two players before slotting past keeper Juan Musso, the visitors leveled moments before the interval.
Four minutes from time, Udinese had the ball in the net but the shot of defender Marvin Zeegelaar was ruled out for his foul on Gollini.