Zlatan Ibrahimovic scored twice on his first start in two months as AC Milan beat Cagliari 2-0 on Monday to pull ahead of city rivals Inter on top of the Serie A table.
Ibrahimovic, 39, got the first from the penalty spot after seven minutes, adding a second just after the break in Sardinia.
Milan, targeting their first league title since 2011 when Ibrahimovic last played in the team, pull three points ahead of Inter who beat champions Juventus 2-0 in the San Siro on Sunday.
"This victory is a sign above all to ourselves more than Inter," AC Milan's boss said.
"We all want to bring Milan back to the top. The team will do everything from here to the end.
"Now we have an important game against Atalanta (Saturday), we focus on that, then in March and April we will see where we are."
The Swede brought his tally to 12 goals in eight games with five doubles, including a brace on 22 November against Napoli, when he picked up the thigh injury which sidelined him.