Watch as Atalanta take their chance with teenager Giorgio Scalvini, but Tammy Abraham and Eldor Shomurodov are wasteful with Jose Mourinho sent off for dissent.
Juan Musso went off in the opening minutes after a clash of heads and Scalvini scored from the edge of the area on a smart Rasmus Hojlund pull-back.
Abraham had two big chances one-on-one with Marco Sportiello, but also had to perform a goal-line clearance to prevent Zeki Celik scoring an own goal.
Mourinho saw red for protesting a mutual shirt tug between Nicolò Zaniolo and Caleb Okoli, while late on Shomurodov turned off target twice.