But while the 35-year-old Israel-Premier Tech rider was left in floods of joyous tears after winning a lung-bursting sprint for the line on Wednesday, it proved a calamitous day for the men supposed to be Australia's biggest hitters on the Tour.

Jack Haig, leader of the Bahrain Victorious team, had to abandon the race after a crash while AG2R Citroen's Ben O'Connor, Australia's top hope to win the title this year, had a disastrous day, finishing more than three minutes down on race favourite, champion Tadej Pogacar.

And there was more Grand Tour misery for Australian star sprinter Caleb Ewan, who took a nasty tumble when running headlong into a protective hay bale which had come loose at the side of the road with 30km left.

Clarke's career-defining triumph came after a chaotic 157km ride from Lille to Arenberg, a tough stage featuring more than 19km of cobbled sectors which had been expected to cause havoc - and certainly lived up to its billing.

Belgian Wout van Aert came home unscathed to retain the overall lead, but it was a huge day for two-time defending champion Pogacar, who gained time over all his rivals including a huge chunk over his Slovenian friend and rival, Primoz Roglic.

Roglic, one of the pre-race favourites, also suffered in the incident that floored Ewan, and ended up losing more than two minutes to his countryman.

But it was the greatest day of Clarke's 13-year pro career after the Melburnian, whose previous career highlights were winning two stages at the Vuelta a Espana and being part of a team time trial win in the 2013 Tour, pulled out all the stops to win by a hair's breadth.

Sprinting out of the remnants of an early breakaway, the Australian timed his final fling perfectly, edging out Dutchman Taco van der Hoorn with a 'bike throw' for the victory after more than three-and-a-quarter hours in the saddle.

Norwegian Edvald Boasson Hagen was third, two seconds down.

Australian Associated Press