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The Rossoneri hammered the visitors as Christian Pulisic was twice on target, and there were also goals from Rafael Leao, Tijjani Reijnders and Ismael Bennacer at San Siro.

That victory marked their first in the league since 7 April (AEST) against Lecce and also ended a six-game winless run across all competitions.

Milan has already watched fierce rival Inter Milan lift the title but secured second place in the table after moving seven points clear of Bologna with two games remaining.

Despite a frustrating, stop-start season, Pioli was at least satisfied to see his team respond to a concerning run of form.

"It was very important to return to winning ways, we were not used to being so long without victories. We suffered this situation, well done to the guys for their determination," Pioli said.

"No team has managed to maintain the level of Inter and we were not able to have continuity to stick with them.

"Ours is a strong team, but one that failed to overcome decisive moments at a certain time during the season."

Nahitan Nandez pulled a goal back in the 63rd for Cagliari, which remains 15th on the table with 33 points, three points above the relegation zone.

"It hurts to have conceded five goals, in the first half we did well defensively, but we were timid," Cagliari coach Claudio Ranieri said.

"Coming here to San Siro against an angry Milan side after the last results was difficult ... the last two matches will determine whether it will be salvation or relegation.

"Now we cancel everything and think about the next ones."