Napoli moved up to second in the Serie A table with an impressive 1-0 away win over Milan at San Siro.
In a game of few chances, Elif Elmas' early strike proved to be the difference. The North Macedonian rose highest at the front post to nod home Piotr Zielinski's corner, getting his side off to a dream start after just five minutes.
Milan thought they had grabbed a valuable point at the death, only for Franck Kessie to see his effort ruled out for offside following a VAR review.
Napoli, who were without the injured Kalidou Koulibaly, Lorenzo Insigne and Victor Osimhen, set up to counter Milan after taking the lead and did so effectively throughout the game.
The Rossoneri enjoyed the better chances overall though, with Zlatan Ibrahimovic glancing a header just past the post and Alessandro Florenzi also going close before the break with a dangerous, low drive.
Milan had several opportunities after the break too. First, Ibrahimovic raced onto Rade Krunic's through pass, only to see his effort tipped over the bar by former Arsenal goalkeeper David Ospina.
20 minutes from time it was Junior Messias' turn to go close, but his curled effort failed to hit the target.
The hosts then thought they had salvaged a draw in the 90th minute when Kessie smashed home from inside the box. But in a moment of real controversy, the referee ruled out the goal as Olivier Giroud was lying prone in an offside position and affecting Ospina's sightline.
Milan boss Stefano Pioli was left fuming at the decision, but their city rivals Inter will likely have a different version or events. Napoli's win means they remain four points clear at the top of Serie A, a margin they earned with a dominant 5-0 victory over Salernitana on Saturday.
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