Britain's Mo Farah won a bronze medal as Kenya's Geoffrey Kamworor won back-to-back World Half Marathon titles in testing conditions in Cardiff.
Farah's time of 59 minutes 59 seconds in a fast-paced race was 27 seconds off his own European record.
Defending champion Kamworor won in 59:10 despite falling at the start, while compatriot Bedan Karoki finished second.
"I'm disappointed," said Farah, adding it was "massive motivation for Rio".
"With great support from the home crowd it would have been nice to win," said the double Olympic and world champion.
"But there were better athletes who won on the day, the guys were strong and I couldn't go with it. I did run a fast time but as an athlete you always want to win."
Peres Jepchirchir led a Kenyan clean sweep in the women's event.
Pre-race favourites Cynthia Limo and Mary Wacera were both beaten into bronze and silver respectively by Jepchirchir in a time of one hour seven minutes and 31 seconds.
Great Britain's Alyson Dixon was the highest-placed home runner in 27th with a time of 1.12:57.
The medal for Farah came in his first entry in the event, and was the first by a British man since 1993, when Carl Thackery took bronze in Brussels.
Kamworor came across the line first in driving rain to back up his 2014 title in Copenhagen with another gold.
Farah outsprinted Ethiopia's Abayneh Ayele in the home straight to finish in wet and windy conditions.