Tunisian Oussama Mellouli won the gold medal in the men's 10km marathon swimming race at the London Olympics on Friday.
German Thomas Lurz was second ahead of Canada's Richard Weinberger.
Australian Ky Hurst was fifth after two laps but faded throughout to finish well off the pace in 20th, one minute and 46.2 seconds behind the winner.
Mellouli added the medal to a bronze won in the 1500m freestyle final in the pool last week.
He becomes the first athlete to win Olympic gold in the pool and open water swimming after defeating Australian Grant Hackett to win the 1500m title in Beijing four years ago.