Proud and patriotic, China's Sun Yang is a worthy successor to distance swimming great Grant Hackett, but will find out in London whether he has the Australian's famed mental toughness, his coach Denis Cotterell said.

Cotterell, a shaggy-haired surfing enthusiast from Australia's Gold Coast, was the mastermind behind Hackett's Olympic gold at the 2000 Sydney Games in the 1,500 meter freestyle and his successful title defense four years later in Athens.

Cotterell (pictured) now stands on the brink of another coaching triumph, with 20-year-old world champion Sun the favorite to win the 1,500 in London, and a leading contender to upset reigning South Korean champion Park Tae-hwan in the 400 freestyle.