WAIS athlete Rhys Mainstone has defeated Olympic silver medallist Thomas Lurz to win the FINA 10km Marathon Swimming World Cup in Hong Kong.

Mainstone claimed the impressive victory in 1:57.30hrs, ahead of a world class field, touching home 15 meters in front of German great Lurz in second and Greece’s Spyridon Gianniotis in third.

The 2012 Australian national champion admitted he felt in good shape throughout the race.

"I arrived in Hong Kong from Perth on Friday and pulled up pretty well from the flight,” he said post-race.

"The main thing is that I was just looking forward to racing. This morning I felt fantastic and once I dived in the water I felt great the whole way”.

Having paced with the race leaders for the first half of the race, Mainstone made his move at the start of the final lap.

"With 4km to go at the feeding station, I had a really quick feed and was able to put a 10 to 15 metre break on the field.”

Having established a lead of some 35m, Mainstone faced some nervous moments as the chase group led by Olympic medallist Lurz appeared to be pulling him in.

"I did back myself from 4km to go, but there was a moment where I questioned it as I was being caught. I just focused on what I’ve been doing in the training pool and am very happy with the end result.

The Mel Tantrum coached swimmer claimed the disappointment of missing London, continues to motivate him towards his future goals.

"Hopefully now there is more to come.”

"I have (the Olympic race) recorded and I replay it a lot of the time.

"It’s going to drive me further over the next four years going into the Rio Olympics.”

Mainstone now heads to China with the last leg of the FINA 10km Marathon Swimming World Cup to be swum in Shantou on 13 October.