Russia's Kirill Abrosimov and Brazil's Ana Marcela Cunha triumphed in the men's and women's races, respectively, at the International Swimming Federation (FINA) Marathon Swim World Series leg at Lake Ohrid in North Macedonia.
Twenty-seven-year-old Abrosimov clocked 2 hours 0min 21.80sec to triumph on the 10 kilometre course.
He led for most of the race and fended off the challenge of his rivals, as a large pack all finished within seconds of each other.
The success was the first for the Russian at this level.
"I wanted to win today and I was hungry for victory," he said.
France's double world champion Axel Reymond finished second in a time of 2:00:21.90.
The 25-year-old entered the event after defending his 25km world title in Gwangju in South Korea last month.
He also won the fourth leg of the FINA UltraMarathon Swim Series, held over 25km, which took place in Ohrid on Saturday (August 24).
Matteo Furlan of Italy was third, clocking 2:00:23.30.
Cunha, a five-time world champion who swum to a pair of golds in Gwangju, won her race in 2:11:38.40.
She has now won four titles on the circuit this season after earlier wins in Hungary, Qatar and Portugal.
Italy collected both minor medals with Olympic silver medallist and rankings leader Rachele Bruni second in 2:11:40.90.
Arianna Bridi won bronze in 2:11:41.30.
Lake Ohrid was the seventh leg of the World Series with two more stops to go.
The circuit now moves to Nantou in Taiwan on September 7, where racing will take place on Sun Moon Lake.