O'Connor attacked from a large breakaway group with 40 kilometres remaining of the 144km mountain stage from Cluses to Tignes.

The AG2R-Citroën rider rode with the Colombian duo Nairo Quintana and Sergio Higuita during the stage, which included two category-one climbs.

Quitana faded after securing enough points to move to the top of king of the mountains classification, with O’Connor then distancing Higuita to move solo.

The Australian briefly threatened to move into the overall race lead with his advantage over the general classification group remaining consistent.

An acceleration from Ineos Grenadiers in support of their best-placed rider Richard Carapaz saw the gap decline, with UAE Team Emirates' Pogačar increasing the pace further as the finish approached.

O'Connor missed out on the yellow jersey, but the Australia was able to celebrate a stage victory in his maiden Tour de France by crossing the line in 4 hours 26min 43sec.

"Just to be taking part on the Tour de France in the first place is a dream," the 25-year-old said.

"Then, to achieve a victory like this one is excellent, a great reward to everyone who has supported me over the years.

"When I crossed the line, I couldn’t hold my tears.

"I’m thankful to AG2R-Citröen, they have put so much faith in me this year."

Italy’s Mattia Cattaneo was second on the stage at 5min 7sec down, with his compatriot Sonny Colbrelli producing a remarkable ride to finish third at 5:34 as he chased points for the points classificiation.

Pogačar finished 6:02 down in sixth, with the 22-year-old gaining another 32sec on Carapaz.

Pogačar leads the race by 2:01 from O’Connor, with Colombia’s Rigoberto Urán lying third at 5:18 behind.

Denmark’s Jonas Vingegaard and Ecuador’s Carapaz are 5:32 and 5:33 off the race lead.

Vingegaard now leads Jumbo-Visma’s general classification challenge, with last year’s runner-up Primož Roglič of Slovenia withdrawing pre-stage due injuries sustained in crashes earlier this week.

Dutch rider Mathieu van der Poel, who led the race for six stages, also withdraw to focus on preparations for the Tokyo 2020 Olympic Games.

Stage three's Belgian winner Tim Merlier and the French duo of Arnaud Demare and Bryan Coquard were among sprinters eliminated on the stage after ending outside the time limit.

A rest day follows tomorrow with racing resuming on Tuesday (July 6) with a flat 190km stage from Albertville to Valence.