Roma slid out of the Serie A top four by the slimmest of margins as they lost 3-1 to Atalanta in Bergamo on Monday.
Jose Mourinho's 100th game as Roma coach ended with a potentially costly loss. His club started the night two ahead of AC Milan on goal difference but ended it outside the Champions League spot on goals scored.
Roma host Milan on Sunday.
Five days ago, Roma were comfortably third in Serie A, but then Juventus jumped to third after their 15-point penalty was suspended. On Sunday, Milan won at Lecce.
Atalanta stayed in the top-four race. They remained in seventh but are four points behind Milan and Roma with seven games to play.
Atalanta took the lead with a volley from Mario Pasalic after 31 minutes. Rafael Toloi fired the second following a corner in the 74th minute.
Roma, who went to extra time and penalties before eliminating Feyenoord in the Europa League last Thursday, showed more fight in the second half after bringing on Paulo Dybala.
Lorenzo Pellegrini scored off the post in the 83rd minute, but Roma's hopes lasted only a few seconds before a handling error by Roma goalkeeper Rui Patricio presented Dutch midfielder Teun Koopmeiners with a goal.