Rhys McClenaghan says organisers wiped chalk off the pommel horse before his World Championships qualifying routine after a competitor tested positive for Covid-19.
The Irish gymnast slipped late in his routine, missing out on a place in the final in Tokyo with a score of 13.766.
The disappointment comes two months after a slip in the Olympics final.
“I’m sad I trained until this point just to have the chalk wiped off the equipment,” he tweeted on Wednesday.
He added that he had been told to wait 90 minutes before competing because a competitor in the subdivision before his had tested positive for Covid.
“Time to go home and just hope there’s not another Worlds like this one,” he wrote.
Artistic gymnasts use chalk on their hands and the apparatus to improve grip.
County Down native McClenaghan had hoped to return to Japan and banish the memories of a disappointing end to his Olympic campaign, after he had become the first Irish gymnast to reach a final.