Ronaldo started his side's crunch Premier League fixture on the bench, with temporary boss Michael Carrick dropping the club's star man in a bold call.
The Portuguese superstar was drafted on in the second-half, replacing goal-scorer Jadon Sancho - but failed to influence the game.
And after the final whistle, his emotions got the better of him as he stormed down the tunnel without shaking hands with Chelsea players.
He also ignored the travelling Man United fans and muttered to himself as he went straight back to the dressing room in frustration after their 1-1 draw at Chelsea, according to the Daily Mail.
:speaking_head: "He's not come back to Manchester United to sit on the bench."- Football Daily (@footballdaily) November 28, 2021
Roy Keane says Cristiano Ronaldo had to play today and doesn't understand why he was on the bench pic.twitter.com/P2NVBJI26e
Ronaldo did the same thing when his team dropped points at home to Everton last month.
The 36-year-old has scored four league goals since returning to Old Trafford.
But Carrick felt the need to start without him for Chelsea and he explained his decision before kick-off.
"A few tweaks and changes from the other night, to change things up a bit," he told Sky Sports.
"Cristiano is probably our standout name, but it's just game-plan, ideas. I had a good chat with Cristiano actually, he was great, and we've decided to go like that today. Really looking forward to the game.
"It's a decision just to pick a team, to be honest. I don't think it needs more drama than that. Everyone is fine, all the boys who have come out of the team have been terrific around the place, Cristiano included, fantastic with the boys, supporting them 100 per cent and ready to come on if and when needed.
"We're happy with the team we've picked, for sure. We've come here to try and win the game, like we do every single game."
Man United resume their league campaign on Thursday when they host Arsenal.
Will Ronaldo start? Watch this space.
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