The Italian won over 10 kilometres in rainy conditions, finishing in 1 hour 56min 11.1sec.

His team-mate Federico Vanelli was second in 1:56:13.7 as Canada's Hau-Li Fan touched for home bronze in 1:56:17.4.

The World Cup event was taking place after marathon swimming action at the FINA World Aquatics Championships in Budapest last week.

Ruffini, who was fourth in the Hungarian capital over 25km, was able to win when Vanelli swum wide in the home straight.

"I arrived at this race very tired because Friday at World Championships I swim 25km," Ruffini said.

"Before this race, when I speak with my coach, he said, 'just swim, don't go for victory, just swim the whole race because you are very tired.'"

Italy made it a day to remember as Arianna Bridi won the women's race in 2:03:15.5.

Brazil's Ana Marcela Cunha was second in 2:04:24.9, in front of her compatriot Viviane Jungblut who clocked 2:04:26.4 for bronze.

"I'm very happy for the second place because last week, I competed in all the races at the World Championships and from Budapest I go to Rio, I go to São Paulo, and I come to Canada," said Cunha.

"I stayed three days in a plane." 

The season will now continue in Chun'an in China on October 15.