The 21-year-old posted a time of 1 hour 49min 48.2sec to finish ahead of The Netherlands’ Ferry Weertman and Greece’s Spyridon Gianniotis, who took second and third respectively at the Kazanka River venue. 

Wilimovsky took over the lead from Hungary’s Gergely Gyurta at approximately the 6km mark and went on to become only the second American swimmer to win the event following Chip Peterson’s gold medal-winning performance at the 2005 World Championships in Montreal.

The top 10 swimmers from the 70-man field all qualified for next year’s Olympic Games, including Gianniotis who will be competing at his fifth Games.

"I am stoked with this win," said Wilimovsky.

"I guess I surprised myself but I know that I have been putting in a lot of work with my coach.

"I was just trying to get into the top 10 and qualify for Rio, so I'm pretty excited.

"I knew this was going to be competitive race and with so many guys it was rough at the beginning.

"I always thought that I would be able to pull away at the end."

Elsewhere on another action-packed day of competition, China maintained their stranglehold on the diving titles as Xie Siyi won the men’s 1m springboard crown and Olympic champion Chen Ruolin claimed her fifth consecutive world 10m synchronised gold medal alongside partner Liu Huixia.

Xie won with a total 485.50 points, while Ukraine’s Illya Kvasha repeated his silver medal from 2013 and Mike Hixon claimed the bronze, the US’s first diving medal of the Championships.

Meanwhile, Chen and Liu led throughout to hold off a strong challenge from Canadians Meaghan Benfeito and Roseline Filion, winning by 20 points with a total of 359.52 in the five-dive final.

North Korea made history by winning their first medal across all the aquatic disciplines in the 42-year history of the World Championships as Kim Un-hyang and Song Nam-hyang took bronze.

There was also further success for Russia in synchronised swimming as the host nation added the team technical title to the technical solo and duet crowns already won.

Russia performed their high-speed “Kaleidoscope” programme brilliantly, earning 95,7457 points, while China and Japan completed the podium with 94.4605 and 92.4133 respectively.

"I think people liked our “Kaleidoscope” programme," said Russia’s Aleksandra Patskevich.

"It’s vivid, it’s bright, full of motion.

"It’s always fun to watch.

"I think people are getting bored when the music is slow."

China’s five diving titles put them top of the medal standings, while Russia and the US are tied on three golds apiece.

The action in Kazan is due to continue tomorrow with the Championships set to run until August 9.



Related stories
July 2015: China regain 10m platform synchro crown at World Aquatics Championships
July 2015: America's Anderson claims first World Aquatics Championships gold medal with 5km success
July 2015: Putin declares World Aquatics Championships open in Kazan after water-themed ceremony
June 2015: FINA to offer record prize fund at this year's World Championships
June 2015: Olympic gold medallist withdraws from Australian World Aquatics Championships team after doping offence