Ronaldinho picked the ideal time to open his AC Milan account as his first-half goal gave them a 1-0 win over city rivals Inter on Sunday.
The Brazilian powerfully headed home a cross from compatriot Kaka in the 36th minute as Jose Mourinho tasted his first defeat as Inter boss.
The Nerazzurri finished the game with 10 men after Nicolas Burdisso was sent off in the 77th minute, while Marco Materazzi was also sent to the stands from the Inter bench for protesting too strongly in a fiery end to the derby.
Carlo Ancelotti’s side look to have banished their woeful early-season form though after their third straight win lifted them up to sixth in the Serie A table.
Inter’s first defeat of the season leaves them fourth, two points behind leaders Lazio.