Robinho and Zlatan Ibrahimovic collected a goal each and an assist each as the Rossoneri overcame Van Bommel's red card to leave the Massimino with three points.
The Brazilian followed up when Mariano Andujar could only parry an Ibrahimovic free-kick to score just four minutes after the Dutch midfielder saw red for a second bookable offence. Ibrahimovic then added a second late on.
Milan could easily have taken the lead inside 50 seconds when Ibrahimovic held off two challengers before teeing up Robinho on the left, but the Brazilian’s curling effort wasn’t close enough to the far corner and Andujar was able to smother the shot.
It was a rare clear opportunity in a fairly even first half. Ciro Capuano attempted to recreate his wondergoal against the Rossoneri at San Siro earlier this season with a flying volley from a narrow angle but saw Daniele Bonera deflect it over. Milan’s giant Swede then had another chance to lay on a charge at goal for Alexander Merkel on a two-on-one break, but his pass was far too nonchalant and proved far too easy for Matias Silvestre to cut out.
Catania were hit by bad news on the stroke of half-time when Ezequiel Carboni was forced off by a groin injury, with Simone Pesce replacing him. The Rossoneri made a change of their own at the beginning of the second period when Urby Emanuelson came on for his league debut, replacing Merkel.
Ibrahimovic | Architect of the first, scorer of the second
The leaders were reduced to 10 men in the ninth minute of the second stanza when Mark van Bommel, who had earlier seen yellow for a foul on Nicolas Spolli, stopped Pablo Ledesma in his tracks and received a second caution from referee Paolo Tagliavento.
This seemed to only bring the fighting spirit out of the Diavolo though, and within four minutes they were ahead. Ibrahimovic’s drilled free-kick forced Andujar into a low save, but the Argentine could only parry the ball into the path of Robinho, who followed up with a fierce finish from five yards.
The goal forced Diego Simeone to change things around, with Adrian Ricchiuti coming on to mix things up as the Etnei finally asked questions of their visitors, but they always seemed just as likely to concede again as they became more stretched.
Eventually Milan grabbed a second when Robinho returned the favour for the first goal. When he was allowed to run free down the right, the Brazilian squared for Ibrahimovic to slide home his 13th goal of the season.
The result sends Massimiliano Allegri’s side seven points clear at the top of the table, while Simeone continues to search for his first point as a coach in Italian football.