Uganda's Jacob Kiplimo broke the half marathon world record with a time of 56 minutes, 42 seconds in Barcelona on Sunday, 48 seconds faster than the previous mark set by Ethiopia's Yomif Kejelcha in October.
Kiplimo's run was the greatest single improvement on the men's half marathon record, World Athletics said on its website.
"It has been the perfect race. Ideal temperature, no wind at all, fantastic circuit, everything went better than expected," Kiplimo said. "I found myself full of energy and decided to inject a brisker rhythm from the third kilometer, but I never imagined to perform under the 57-minute barrier; that's astonishing.
He said his next race would be at the London Marathon in April. It would be his first marathon race.
Kiplimo, 24, won bronze in the 10,000 meters at the Tokyo Olympics in 2021 and is a two-time cross country world champion.
Japan's Toshikazu Yamanishi also broke the men's 20-kilometer race walk world record Sunday, clocking 1:16:10 in Kobe, Japan, to beat the mark set by his compatriot Yusuke Suzuki in 2015.
Reuters contributed to this report.