Rasovszky holds on to win men's open water 10km
The 26-year-old Hungarian won in 1 hour 48 minutes and 21 seconds to claim his first gold at the distance in an international championship.
His previous world championship gold in 2019 came in the 5km event.
Leading for most of the race, Rasovszky helf off a spirited comeback by Frenchman Marc-Antoine Olivier, who was second 2.40 seconds behind.
Great Britain's Hector Pardoe took bronze at 8.00sec.
The top 15 finishers qualified for the Paris Olympics, where the event will be held in the River Seine.
Defending champion Florian Wellbrock, who won last year's world championships in Fukuoka, could oinly finish 29th but the German has already secured his place in Paris.