In the minutes immediately following half-time, and with the match goalless, referee Gianluca Rocchi decided to stop play amid consistent chants towards Milan's black players emanating from the away end.
A stadium announcement was then made ordering offenders to cease chanting before play was allowed to resume.
Roma captain Francesco Totti and his Milan counterpart Massimo Ambrosini were among the senior players who had complained to Rocchi before he suspended play.
The Italian Football Federation introduced new rules to help referees tackle racist behaviour in the wake of Milan midfielder Kevin-Prince Boateng's decision to walk off the pitch in a January friendly against Pro Patria in the face of abuse.
Referees are now able to call matches to a halt for an announcement to be made demanding an end to chants.
Should any such announcements fail to have an effect on offenders, match and stadium officials are ultimately authorised to abandon the game.