Anna Kiesenhofer produced a stunning ride to win gold in the women's cycling road race, with the result certainly taking second-placed Annemiek van Vleuten by surprise.

Kiesenhofer was part of a five-strong breakaway group that immediately moved clear before slowly dropping each of her rivals during the 137-kilometre route that concluded at the Fuji International Speedway track.

The Austrian was all alone at the head of the field with around 40km to go and, with other nations unable to organise a pursuit with team radios not in use, she ended up finishing 75 seconds clear.

"It feels incredible. I couldn't believe it," Kiesenhofer said after claiming the biggest victory of her career to date.

"Even when I crossed the line, it was like, 'Is it done now? Do I have to continue riding?' Incredible."

Such was the huge gap, Van Vleuten initially thought she was victorious when crossing the line, only to be quickly informed that was not actually the case.

"Yes, I thought I had won. I'm gutted about this, of course," she confirmed to the media afterwards.

"At first I felt really stupid, but then the others (her team-mates) also did not know who had won."

Still, Van Vleuten can celebrate securing an Olympic medal five years on from the horrific crash when leading the race at the Rio Games.

At the head of the field with 10km remaining, she came off her bike during the final descent, suffering severe concussion and small fractures to her back.

Elisa Longo Borghini claimed the final place on the podium this time around, securing a bronze medal in the road race for a second successive Olympics.

The Italian finished ahead of Lotte Kopecky of Belgium and Marianne Vos, the Dutch rider who triumphed at London 2012.