The referee consulted his assistant behind the goal and chose to show Ronaldo a straight red card, with the contact he made with Murillo's head likely to be the reason for the sending off.
Rather than telling the two grown men to stop acting like four-year-olds and let play continue, referee Felix Brych got all puffed up and marched over to administer a straight red card to Ronaldo.
Allegri expressed his delight with the performance of his team, with Miralem Pjanic's two penalties proving the difference in a 2-0 win over Valencia.
Cristiano Ronaldo has a long and proud history in the Champions League having won it five times during his career, although his first ever sending off in the competition caused a certain amount of controversy as Twitter was in uproar on Wednesday night.
- The last Champions League game to see three penalties awarded was Sevilla against Borussia Monchengladbach in 2015.
Road access cut off to N. Carolina city after Florence
President Trump declared a state of emergency in SC on Monday ahead of the storm, which moved into the state late Friday. A man tries to corral escaped horses in the floodwater caused by Hurricane Florence in Lumberton , North Carolina.
Kavanaugh's accuser NOT ready to testify against Trump's supreme court nominee
Any defections from Republicans' narrow Senate majority could sink the nomination and deal a major setback to Trump. Committee Republicans have planned for only Kavanaugh and Ford to testify, but Democrats want other witnesses, too.
No regrets over Arsenal job for stand-in City manager Arteta
If I had to choose, I would choose Pep to be on the touchline because he does that better than anyone else. When things happen, you have to make decisions and sometimes you don't have time to make decisions.
Ronaldo's departure made little difference to the reigning Italian champions though, as his teammates went on to record a 2-0 victory in Spain.
There was a third penalty in the match deep into stoppage time but Daniel Parejo saw his effort saved by Wojciech Szczesny as Valencia were denied a consolation goal.
Jose Mourinho's men were inspired by Paul Pogba on the artificial pitch, as the French World Cup victor drilled home a brilliant opener before converting a penalty on the stroke of half-time, and setting up Anthony Martial for the third.
The introduction of Sergio Aguero as a substitute revitalised City after the break, and Bernardo Silva turned in Leroy Sane's cutback with 23 minutes still to play.
German side Hoffenheim and Shakhtar Donetsk shared an entertaining 2-2 draw in Ukraine in the other Group H clash.