Hungary's Kristof Rasovszky stormed to the men's five-kilometre open water title in a brutal race Saturday, winning the first gold medal of the world swimming championships in South Korea.
The 22-year-old clocked 53 minutes, 22.10 seconds in choppy conditions with Frenchman Logan Fontaine edging out Canada's Eric Hedlin to take silver just over 11 seconds behind at Yeosu EXPO Ocean Park, around 100 kilometres south of the competition host city Gwangju.
Rasovszky, who completed the 5km and 25km double at last year's European championships, went out aggressively and never allowed himself to get sucked by the pack in a race that began two hours early because of the threat of bad weather.
The Hungarian did briefly trade the lead with Fontaine on the fifth lap of nine but the Frenchman was unable to sustain the pressure and faded over the final laps before mounting a furious late fightback for silver, improving on his European bronze.
"There were no tactics, just go," said Rasovszky. "There was a tremendous fight at the turns so it was better to stay in front and not be part of that."
Fontaine suggested he might look to qualify for next year's Tokyo Olympics in the pool.
"I'm super-pleased," he said. "But it may be the right dynamic for me to try that -- why not?"
Hedlin was delighted with bronze, six years after taking silver at the 2013 world championships in Barcelona.
"It was quite a zoo out there -- there was a lot of elbows and everything," said the Canadian.
"But I'm so happy, it's been six years but I'm back."
The men's 10km race takes place on Tuesday and the punishing 25km on Friday.
Before that, the women's 10km event is scheduled for Sunday with the 5km to follow Wednesday and the 25km on Friday.