Melloli, who clinched the first gold medal for Tunisia since 1968, finished in 14 minutes and 40.84 seconds to beat world record holder Grant Hackett of Australia.

"Thank God for this gift, I am very happy with the gold medal, and I hope I could pave the way for Arab youth to win more medals in future," said the 24-year-old.

Mellouli returned to competition this summer after he was banned for 18 months in November 2006 for testing positive for Adderall, which the Tunisian claimed to be unaware of its prohibition.