The Rossoneri made a bold move by starting Kevin-Prince Boateng, Stephan El Shaarawy and Giampaolo Pazzini up front in a 4-3-3 formation.
The attacking trio did not disappoint as Pazzini scored twice and Boateng scored once in the 3-0 victory.
The match was turned on its head in the 16th minute when Lazio winger Antonio Candreva was sent off after pulling down El Shaarawy on the edge of the penalty area.
While AC Milan did not score off of that free kick, the sending off of Candreva did change the complexity of the match.
In the 40th minute, the floodgates were opened by Giampaolo Pazzini, who scored on a rebound.
Lazio keeper Federico Marchetti was unable to hold on to a shot by Ignazio Abate, and Pazzini pounced on that error and put home his 11th goal of the season.
Just four minutes later, AC Milan capitalized on another rebound as Boateng scored his second goal of the season.
The rebound that Boateng scored off of came as a result of a blistering header that Pazzini put on goal.
Once again, Marchetti was unable to hold on to the ball, and Boateng pounced to put the Rossoneri ahead by two going into the half.
In the second half, Pazzini showed a glimpse of his individual talent as he unleashed a shot that found its way into the bottom-right corner of the net.
Both Pazzini and Boateng were taken off in the second half as the victory was secured by the 60th-minute strike of Pazzini.
The victory boosted AC Milan up into third place over Lazio, over whom they now have a one-point lead in the race for the third and final UEFA berth.