The Bora–Hansgrohe cyclist took the jersey from Pogacar's UAE Emirates teammate Adam Yates after the first mountain stage, and leads second-placed Vingegaard by 47 seconds and sixth-placed Pogacar by one minute, 40 seconds in the general classification.

"I can't believe it. I didn't really expect this when I rolled out of bed this morning," said the Tour de France debutant.

"I've been watching the Tour since I was a little boy, when I was six-years-old, and I never thought I'd find myself in the yellow jersey, but here we are."

Only the second Australian to win a Grand Tour with victory in last year's Giro d'Italia, Hindley had mapped out a conservative strategy to tackle the stage but ended up joining a large breakaway before the first climb.

The improvisation proved effective as Hindley broke clear to celebrate victory with his touring family.

The Australian said he had been locked down in altitude training camps and course reconnaissance for months before his debut Tour.

"Basically, living like a monk for the past two months or so and living out of a suitcase, which is good fun," Hindley said.

"I haven't really seen my family too much, nor anyone else too much, but that's what you have to do if you want to be competitive.

"It's really special for me to have them here and have them supporting roadside. I owe those people everything, and they're everything to me."

The rivalry between Danish defending champion Vingegaard and twice Tour winner Pogacar will remain the focus ahead of another testing stage six through the Pyrenees but Hindley believes the general classification is wide open.

His parents said the stage win was 20 years in the making, with Hindley having determined at the age of seven that he would be a pro cyclist.

"He likes to strive, and to get to the next thing and the next thing," his mother Robyn told the Australian Broadcasting Corporation.

"And he's been a slow burn to be here, just small steps every year, and learning. He's making another step."