Francis Ngannou posed for pictures with Andre Onana after Manchester United beat Bodo/Glimt 3-2 on Thursday.
But then went a step further and the United physios may have had their hearts in their mouth for a brief moment.
Onana and Ngannou caught up on the Old Trafford pitch after Thursday's game
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Onana and Ngannou caught up on the Old Trafford pitch after Thursday's gameCredit: Getty
That's because the MMA star wrestled the Red Devils goalkeeper to the ground started play fighting with him.
The 6ft4in former UFC heavyweight champion, and current PFL star, had his Cameroonian compatriot in full mount and pretended to start his ground-and-pound offence.
Video has emerged of what happened on social media, with the pair laughing and joking about it, making it clear no harm was done and Ruben Amorim can rest easy.
They posed for photos, which were posted online by Onana after the goalkeeper played 90 minutes - who was lucky to escape a red card for a handball outside the area.
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The pair appear to be firm friends, having been spotted catching up on a Man United pre-season tour last year.
It was far friendlier than when a similar incident occurred with Conor McGregor at Arsenal in October.
Following the Gunners' 2-0 win over Paris Saint-Germain, McGregor made his way down onto the Emirates turf.
He was seen playing football with Bukayo Saka and Declan Rice, before play-fighting with the former.
Saka could even be heard telling the Notorious to be careful as a flurry of punches and kicks were thrown in his direction.
The pair started wrestling, but it was all fun and games
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The pair started wrestling, but it was all fun and games
McGregor showed off a range of MMA moves on a slightly worried Arsenal star Saka
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McGregor showed off a range of MMA moves on a slightly worried Arsenal star SakaCredit: thenotoriousmma
McGregor even started grappling with the star Arsenal forward as if he were going to throw him, before stopping.
The incident caused so much concern for the Gunners that the club held an inquiry.
The club were reportedly considering making changes to their matchday rules as a consequence.
For Ngannou, he was also spotted in the crowd with Derek Chisora, who this week said he could fight the Cameroonian for his 50th overall bout in the ring.
He told talkSPORT: “Another push I'm trying to get through is a fight with Ngannou - in Africa.
"I want to push that. If I can get Francis Ngannou in Africa for our own African people to see us perform, instead of us performing in European countries and Saudi, it will give just a little bit of a taste to our young and upcoming talent in Africa to see African warriors go at it."