Rafael Leao was sent off and Charles De Ketelaere had a goal disallowed, but 10-man Milan still scraped a 2-1 victory with Junior Messias and the Olivier Giroud penalty, rescued late on by Mike Maignan.
The Rossoneri were coming off their Derby della Madonnina victory and a midweek Champions League draw with RB Salzburg, but Divock Origi was the latest addition to the injury list, along with Alessandro Florenzi, Ante Rebic, Rade Krunic and Zlatan Ibrahimovic. Samp already held Juventus and Lazio to draws here, but Omar Colley and Harry Winks were unavailable.
Theo Hernandez made a decisive block to stop Medhi Leris volleying in from 12 yards on a Tommaso Augello cross, but Milan broke the deadlock instead.
Rafael Leao started the run from midfield, combined with Olivier Giroud and Charles De Ketelaere then prodded it into the path of Junior Messias, who blasted the low finish past Emil Audero at the near post.
Filip Djuricic thought he had equalised for Sampdoria a few minutes later, but his scorching curler from the edge of the area smashed against the crossbar.
De Ketelaere had the ball in the net for the first time in his Serie A career on 21 minutes when Audero missed Leao’s cross and it bounced in off the Belgian’s shoulder. However, the goal was disallowed after a VAR on-field review because Giroud was offside and interfering with play when causing Alex Ferrari to head the ball to Leao in the first place.
Audero made a desperate save from close range on Giroud from a Theo Hernandez assist, then in the same move the striker turned just wide from Leao’s pass.
The game changed straight after the restart when Leao attempted an overhead kick and instead caught Ferrari. It was his second yellow card, the first awarded rather harshly for what was considered to be an elbow on his marker. This is a potentially disastrous dismissal not just for the game, but also because he’ll be suspended against Napoli next week.
Sampdoria took full advantage to equalise when Augello whipped in a cross from the left and Djuricic got there before Maignan at the near post for a glancing header. Milan wanted the offside flag, but he was behind the line of the ball and therefore could not have been offside.
Audero fingertipped a Theo Hernandez effort over the bar and VAR intervened again when Gonzalo Villar was caught using his hand to deflect a Giroud header on the resulting corner. It was an inevitable penalty, which Giroud converted into the top corner.
Sabiri had penalty appeals, but he seemed to run into Simon Kjaer more than anything else, and the referee was right there to wave play on.
Aster Vranckx made his Milan debut, but Samp had an extraordinary triple opportunity on 87 minutes. First Maignan at full stretch got his fingertips to a Manolo Gabbiadini angled drive, then Valerio Verre somehow kept it in at the by-line and hit the crossbar, and finally Maignan used his chest to charge down another Gabbiadini attempt at the near post.
Samp pinned the 10-man champions back throughout stoppages, but Marco Giampaolo and another member of the Sampdoria bench were sent off for dissent.
Sampdoria 1-2 Milan
Messias 6 (M), Djuricic 57 (S), Giroud pen 67 (M)
Sent off: Leao 47 (M)