Coryn Rivera produced a superb late surge to win the 2017 RideLondon Classique in a sprint finish.
The American, 24, started her sprint from deep, hauling in her rivals before kicking again to push Finland’s Lotta Lepisto into second on the Mall.
Germany’s Lisa Brennauer led out the sprint and held on in wet weather to finish third in the 66km race around a central London circuit.
Dutch rider Marianne Vos was fourth with 2016 champion Kirsten Wild fifth.
“I’m absolutely elated – they were not the best conditions but when you’ve got a goal, you’ve got to commit and get after it,” Team Sunweb rider Rivera told BBC Sport.
“I knew I was in the right place and just had to time my sprint correctly – it’s a very long sprint so it’s a bit deceptive but I went at the right time and pulled it off.”
The Classique, part of the women’s WorldTour, is the richest women’s one-day race with a prize pool of 100,000 euros (£89,500), which matches the total prize pool for the men’s race on Sunday.
“I’m really excited that this race understands we race just as hard, just as crazy as the men and so it’s special to me they respect that,” added Rivera, who won the women’s Tour of Flanders in April.
“To win on my first time racing here is pretty special, too.”
Rivera’s Canadian team-mate Leah Kirchmann won the sprints competition for amassing the most points in the three sprint finishes on laps three, six and nine of the 12-lap race.
Britain’s Katie Archibald won the first intermediate sprint and was fourth at the second but could not contest the third before she eased home in 80th place.
Compatriot Hannah Barnes was the highest-placed Briton in 17th as she faded from contention in the final stages, with her Canyon SRAM Racing lead-out rider Brennauer instead having to strike out alone.