Cristiano Ronaldo is growing "increasingly impatient, frustrated and angry" with life at Manchester United.

That's the view of a leading body language expert who has analysed footage of the five-time Ballon d'Or winner on the Red Devils' bench during Sunday's 6-3 defeat at Manchester City.

Ronaldo, who has scored 699 career goals at club level, was United's only unused outfield substitute at the Etihad - despite his side needing to chase the game for much of the 90 minutes.

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Why did Erik ten Hag leave Ronaldo on the bench v Man City?

After the match, United boss Ten Hag claimed that he had not introduced Ronaldo to the action out of "respect for his big career", per the Daily Mail.

With United already 4-0 down at the break, not even Ronaldo at his very best would have been able to turn things around for Ten Hag.

According to body language specialist Darren Stanton, though, Ronaldo appeared to resent the fact that he wasn't given the opportunity to try.

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What did Ronaldo's body language at Man City show?

Having examined footage of a forlorn Ronaldo on the United bench, Stanton gave his verdict on the Portuguese superstar.

"A micro expression is a very quick flash that the face makes on an unconscious level which reveals the person’s real internal emotion and is only visible for about less than a second, if you know what to look for it’s very visible," he began, via The Mirror.

"As we look at the footage of Ronaldo, he makes a one-sided smile so the left-hand side of his face and cheek wrinkles puff up. This is the emotion of contempt so he has nothing but disdain, a little bit of anger, frustration and impatience for what is happening on the pitch, as he’s on the bench, it’s clear he’s unhappy that he’s not playing and feels a great sense of desperation."

Ronaldo warming up v Man Ciity

MANCHESTER, ENGLAND - OCTOBER 02: Cristiano Ronaldo of Manchester United looks on ahead of the Premier League match between Manchester City and Manchester United at Etihad Stadium on October 02, 2022 in Manchester, England. (Photo by Laurence Griffiths/Getty Images)

Forced to watch on as City pair Erling Haaland and Phil Foden both helped themselves to braces in the first 45 minutes, television cameras panned to Ronaldo, who had his head in his hands.

"Ronaldo also puts his head in his hands which is a classic sign of frustration. It’s also a self-reassurance gesture indicating an increase in the level of frustration and impatience that is growing within him.

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Is there an agenda against Ronaldo at Man Utd?

"I think Ronaldo is thinking there is potentially some sort of agenda why he continues to be placed on the bench and not on the pitch at crucial moments. So overall, Ronaldo is not a happy player and I predict this will happen for many games this year. Ronaldo has increasingly seemed very impatient, frustrated and angry in recent months," Stanton concluded.

If Ten Hag's squad rotation policy in European competition continues, Ronaldo could well start for United in their Europa League clash with Omonia on Thursday evening.

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With all due respect to the Cypriot side, though, Ronaldo clearly wants to be playing a far more significant role at Old Trafford.

Time will tell if Ten Hag is willing to change course and offer him more frequent first-team involvement.