Inter loanee Matteo Politano scored the only goal as Milan's Serie A title hopes were dealt another huge blow with a 1-0 defeat at home to Napoli.

Antonio Conte's Inter moved nine points clear at the summit thanks to a late 2-1 win at Torino earlier on Sunday and that gap remains the same following stuttering Milan's fifth league loss of the campaign.

Both sides lacked quality in a low-key first half but it took just four minutes of the second for Napoli winger Politano to make the breakthrough at San Siro.

Milan had a late penalty appeal rejected for Tiemoue Bakayoko's challenge on Theo Hernandez, shortly before substitute Ante Rebic was sent off for dissent, as Napoli stretched their unbeaten league run away in this fixture to a sixth game.