Australian Chloe Hosking sprinted clear of the field to win La Course on the Champs Elysees in Paris.
The 25-year-old came home ahead of Finland's Lotta Lepisto and Olympic champion Marianne Vos.
There were several crashes on the 13-lap 89km course with Hosking's Wiggle High5 team-mate Dani King one of those involved.
British world champion Lizzie Armitstead withdrew before the start to concentrate on the Olympics.
Armitstead, who won silver in the London 2012 road race, has seven victories this year, including the prestigious Tour of Flanders.
However, the 27-year-old missed her defence of the British title and had to withdraw from the Giro Rosa through illness.
"Going into Rio, I want gold. I would be disappointed with anything else." the Yorkshire rider said on Wednesday. "Those are my ambitions, and they're very different to London."
Armitstead's absence left the Wiggle High5 trio of King, Lucy Garner and Amy Roberts, along with national champion Hannah Barnes, as the remaining four British riders in Sunday's race - the curtain-raiser to the final stage of the Tour de France.
King and Barnes were involved in separate breakaways, but the peloton reeled both back in to set up the expected sprint finish with Hosking's power proving decisive.
"To cross the line first is crazy," she told ITV.
"I was like, 'are they coming, are they coming?', and they didn't."