Inter Milan secured fourth place in the Serie A table by beating Empoli 2-1 at San Siro on Saturday.
All three goals arrived before half-time, with Mauro Icardi reaching 16 for the season before Croatian forward Ivan Perisic responded to Manuel Pucciarelli's equaliser.
Roberto Mancini's men can no longer be caught by fellow Europa League chasers Fiorentina after building a seven-point gap over the Tuscans, who have two games left to play.
Carlos Bacca's first-half penalty proved enough to lift AC Milan back into sixth place following a scrappy 1-0 victory over 10-man Bologna.
The Rossoneri were last week dislodged from the final likely European berth by surprise package Sassuolo, and Cristian Brocchi's men needed to react strongly at the Stadio Renato Dall'Ara.
Their task was made easier by Amadou Diawara, the Bologna player who was sent off early in the game, and Angelo da Costa's foul on Luiz Adriano allowed Bacca to convert from the spot.
Sassuolo can return to sixth with victory at relegation-threatened Frosinone on Sunday afternoon.