Zlatan Ibrahimovic bagged a brace at Marassi, while Hakan Calhanoglu and Rafael Leao rounded out the scoreline, Gianluigi Donnarumma saved a penalty and Sampdoria saw a spectacular debut goal.
Milan dominated the match at the Stadio Luigi Ferraris, taking an early lead through Ibrahimovic, who then set up Calhanoglu for a strike that was originally disallowed for a foul, but given following the VAR review.
The Turkey international returned the favour with an assist for Ibra and substitute Rafael Leao curled in a splendid final strike.
Samp had their chances too, but Donnarumma parried yet another penalty, although even he could do nothing on the debut Serie A long-range stunner from Kristoffer Askildsen.
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