Annemiek van Vleuten saw off the challenge of Netherlands team-mate Anna van der Breggen to claim gold in the Road World Championships time trial in Bergen.
The 34-year-old managed to deal with the tricky conditions better than anyone else on Tuesday as she stopped the clock after 28 minutes and 50.35 seconds.
That time gave her victory by 12 seconds from her compatriot - and team-mate for this weekend's road race - Van der Breggen, an impressive one-two for the Netherlands squad.
"I still cannot believe it," said the new champion. "This season I've surprised myself with what I can do.
"To be world champion in the time trial, I never thought I'd be able to do this. This year I started to believe in it, and to be able to finish it off is incredible."
Former winner Ellen van Dijk's fifth place completed a good day for the Dutch, which will act as a warning sign to the other squads for Saturday's race.
Van der Breggen was the second rider to tackle the 21.1-kilometre course and her time of 29:02.51 looked like being enough as rain made the route difficult to navigate, leading to some pre-race favourites losing time.
Former winner Lisa Brennauer had to settle for 12th overall at nearly two minutes down, while defending champion Amber Neben was one place above her as she failed to make the top 10.
There was much expected of American Chloe Dygert and the 2015 junior road and time trial world champion almost delivered a medal on her debut, the 20-year-old just missing out on a podium place.
She was denied bronze by Katrin Garfoot, the Australian repeating her achievements from 12 months ago and she stopped the clock 18 seconds behind Van Vleuten's winning time.
1. Annemiek van Vleuten (Netherlands) 28:50.35
2. Anna van der Breggen (Netherlands) +12.16
3. Katrin Garfoot (Australia) +18.93
4. Chloe Dygert (United States) +37.95
5. Ellen van Dijk (Netherlands) +52.06