AC Milan won 3-0 at Juventus on Sunday to leave Cristiano Ronaldo and his teammates facing the prospect of Europa League football next season.
Brahim Diaz opened the scoring in Turin in first-half stoppage time and Ante Rebic and Fikayo Tomori completed the scoring late on.
Milan could even afford to miss a penalty early in the second half through Franck Kessie as they moved ahead of Juve in the table.
With three games to go in Serie A, Atalanta and Milan have 72 points, joining Inter, who have already clinched the title, in the top three.
Napoli are in the fourth and final Champions League place with 70 points, closely followed by Juve, who have 69 points.
The 3-0 win was crucial for Milan because it means if they finish level with Juve, they will finish above them in the table because they have the head-to-head advantage.
Andrea Pirlo's side, therefore, are relying on other results to qualify for the Champions League as things stand.