Juventus play Jose Mourinho's United at Old Trafford on Tuesday, October 23.
The Portuguese player then made contact with Murillo's head while urging him to get up. Ronaldo dropped to the floor like the tournament was lost after German official Felix Brych brandished the red card but Juve showed more composure, Miralem Pjanic scoring twice from the penalty spot to clinch a comfortable 2-0 win.
Juventus then play Jose Mourinho's United at Old Trafford on Tuesday, October 23, before hosting the English club in Turin on November 7 in Group H.
Ronaldo, a five-time Champions League winner, first won the competition with United in 2008 before leaving for Real Madrid a year later.
He moved to Juventus in July after nine years in the Spanish capital, and has so far scored three goals in Serie A for his new club.