An athlete has missed out on winning a triathlon after he did a silly celebration early and ended up being overtaken a whisker before the finishing line.

A spectator filmed the tragicomic scene as it unfolded at the triathlon in the city of Sagunto in Spain’s eastern Valencia Province on Sunday 20th June.

The footage shows how Mateo Bustos sees nothing between himself and the finishing line, so he decides to slow down and do a fist pump and a funny walk while facing the crowd

However, a determined runner on his tail whom he had failed to notice starts sprinting and overtakes him just metres before the finishing line.

An incredulous Bustos can then be seen putting his head in his hands as a female spectator shouts: “Idiot! How can he be so stupid?”

The same woman can then be heard saying: “No way! How can he do such a thing? I told him ‘run or he’ll catch you up’.”

As a result of his actions, the athlete from Club Multiesport Benitatxell was pipped to the post by German Cister of Club Triatlon TriCanet.

The footage quickly went viral, racking up tens of thousands of views on social media and attracting comments like: “It’s as if Cristiano celebrated the goal before scoring.”

Other netizens, however, accused Cister of a lack of sportsmanship, suggesting he should have let his compatriot win the race.

As part of the gruelling race, the competitors swam a distance of 750 metres (2,461 ft), cycled 20 kilometres (12.4 mi), and ran five kilometres (3.1 mi).