Two players with Roma connections, Andrea Bertolacci and Philippe Mexes, were on target as Milan picked up their third consecutive victory thanks to a 3-1 Serie A win at Lazio.
Milan had failed to beat Lazio in their past five visits to Stadio Olimpico but goals from Bertolacci, Mexes and Carlos Bacca settled Sunday's contest, although the win was overshadowed somewhat by concerns for Alex who was knocked unconscious during the second half.
Bertolacci, born in Rome, endured a mixed homecoming. The Italy international, who came through the youth ranks at Lazio's fierce rivals Roma, tapped in the opener after a poor piece of goalkeeping from Federico Marchetti but was forced off injured soon after.
Alessio Cerci also hit the post in a first half dominated by Milan, and the visitors had a second when Mexes, who spent seven years at Roma, headed home the second less than a minute after replacing Alex.
It was a particularly sweet moment for Mexes, who in last season's corresponding fixture - a 3-1 defeat for Milan - was sent off and later hit with a four-match ban for grabbing Stefano Mauri by the throat.
Sinisa Mihajlovic, who won Serie A during a six-year stint with Lazio as a player, then saw his side put the game beyond reach with Bacca's late goal and, although Ricardo Kishna bagged a late consolation, Milan leapfrogged their opponents in the table.
Lazio saw tentative penalty claims waved away in the fifth minute when Lucas Biglia was barged to ground by Riccardo Montolivo.
When the action restarted, Mexes made a stunning impact as a substitute, leaping highest to head home Bonaventura's excellent whipped free-kick.
Lazio restored some pride when Kishna fired home at the near post from the left of the box in the 85th minute, but it was too little too late.
