The 31-year-old said he was told by race officials that he was recorded travelling at more than 82 km/h on his downhill finish.
Official records do not exist for high-speed finishes in WorldTour events, but it would at least amount to a new unofficial mark.
Tour de Suisse
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Watch the finish back to see just how fast Mezgec's winning sprint was:
'Oh my word!' - Mezgec flies past Gaviria to take Stage 2 victory in Poland
As noted by Cycling News, Mezgec’s speed is 1.2 km/h faster than the previous best at the event by Jonas Van Genechten in 2014 and Marcel Kittel's speed of 78.3 km/h in 2010.
"This sprint is really special. It’s such a high speed and the last kilometre is very straight. You need a bit of luck, big gears and good timing," Mezgec said after his triumph.
"The speeds are over 80km/h an hour. I’ve got second third and fourth here, but it's a big lottery to win. You need a lot of luck in a sprint like this."
The Slovenian revealed that he was told by the organisers he had travelled at "82 point something" when he received his 'fastest sprinter' award.
"I knew when I had to start, and I had to come from behind because in a sprint like this, when you are second wheel, you don’t do too much," he said. "But when you are ahead you do a lot more work than in second place."
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