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Facebook's Mark Zuckerberg appears to get grumpy with a ref - after losing a jiu-jitsu bout.
The Meta CEO was filmed fighting an unknown competitor in Redwood City in California on Saturday (6/5).
The video shows the Facebook founder attempting to pin his opponent before getting pinned to the floor himself.
Eventually, the ref calls the match and gives the win to his opponent - believing that Zuckerberg, 38, had 'tapped out'.
Onlookers say the confused and shocked billionaire is seen to be furious claiming it was an error - and the match is eventually re-cast as a 0-0 draw.
The 'controversial' call seems to satisfy Zuckerberg in the footage, who hugs his opponent.
Zuckerberg later won gold and silver medals at the event - his first public competition.
It was revealed in September last year that he had taken up mixed martial arts (MMA), with his trainer has describing him as a "silent killer" in the ring.