Fredy Guarin scored the only goal as Inter defeated Milan 1-0 on Sunday at the San Siro in the first Milan derby of the Serie A season.
Following a scoreless first half, Guarin netted a superb solo strike in the 58th minute for what turned out to be the winner. Mario Balotelli, making his second debut for Milan, entered as a substitute but could not score an equalizer despite playing well.
The win maintained Inter's perfect start through three matches. Roberto Mancini's side top the table with nine points, two ahead of Chievo Verona.
Milan, meanwhile, lost for the second time in three matches.