Germany's Judith Arndt exacted revenge on British defending champion Emma Pooley with victory in a rainy World Road Cycling time trial in Denmark.
Pooley raced to bronze on wet roads in a time of 37 minutes 31.51 seconds, 24.13 seconds off Arndt's winning time.
Pooley outpaced Arndt by 15 seconds last year to become the first British female world time trial gold medallist.
New Zealand's Linda Villumsen took silver this year in Copenhagen as Julia Shaw, 46, finished 17th for GB.
"You're against the clock, all you can give is your absolute best - and if you don't feel like being sick and dying at the end of the race then you haven't tried hard enough," Pooley told BBC Radio 5 live sports extra.
"I'm pleased with the result. It was not the nicest day, to be honest, and the course is quite technical. There were quite a few corners and lots of paint on the road which makes it slippery when it's raining.
"I'm more of a climber. I would have liked there to have been some kind of seismic activity in Copenhagen, and a mountain to have appeared."
Arndt, who had second-place finishes in 2003 and 2004 to add to silver in 2010, said: "This has been a goal for me for a very long time. I've had silver and bronze a few times, and now finally gold.
"There were a lot of corners and the course was wet, but I was able to handle everything and had no mistakes or mechanical issues."
Times slowed noticeably once the rain took hold 45 minutes into the 2011 event and, while the weather gradually cleared, the going remained very wet over Copenhagen's twisting, cobbled course.
Canadian 38-year-old Clara Hughes, a silver medallist at this event in 1995 who embarked on a successful speed skating career before returning to cycling, held the fastest time for most of the day.
Hughes had the advantage of having completed half of her time trial on dry roads before the rain set in.
But Arndt, 35, put more than 20 seconds between herself and any other rider as she mastered the conditions in a time of 37:07.38, which Pooley could not touch. Shaw, 46, finished in 38:57.26.
Pooley now expects to ride in support of team-mate Lizzie Armitstead in Saturday's road race, adding: "The road race has more hill than the time trial but is not exactly mountainous.
"We'll probably be riding for Lizzie and she's in awesome shape."
Jon Dibben earlier posted an eighth-place finish for Britain in the junior men's time trial, finishing in a time of 35:55.72, 48 seconds off leader Mads Wurtz Schmidt of hosts Denmark.
Fellow junior Elinor Barker raced to a surprise silver medal in the women's race a day earlier, despite British Cycling having placed "no expectations" on the junior team.
The 17-year-old from Cardiff finished 1.84 seconds behind Australia's Jessica Allen.
Bradley Wiggins and David Millar take to the course for Britain in Wednesday's men's time trial.
"I think Bradley is going to be flying the flag for us," said Millar on Tuesday. Tony Martin and Fabian Cancellara are seen as Wiggins' main rivals for the world title.