AC Milan returned to the top of the Serie A table after beating Benevento 2-0 on Sunday, despite playing more than half of the match with ten men.
Inter had overtaken their city rivals with a win over Crotone in Sunday's early kick-off in Italy but Stefano Pioli's side retook their place later on in the day.
Milan edged in front at the Stadio Ciro Vigorito from 12 yards, with Frank Kessie finding the top corner with his penalty kick.
However, the visitors were reduced to ten men later in the first half when Sandro Tonali's challenge on Artur Ionita earned him a red card following a VAR review.
Rafael Leao's goal shortly after the break gave Milan a considerable lead to defend and, but for a missed penalty by Benevento's Gianluca Capriani, they managed to keep the hosts at bay.