SAN DIEGO -- Bernard Koech of Kenya won the Rock 'n' Roll Half Marathon in 58 minutes, 41 seconds, the fastest time ever run in America and the fastest in the world this year.
Koech's mark will not count as a record because the net elevation drop from start to finish on the point-to-point course exceeded IAAF rules.
Still, it was the first time the half marathon overshadowed the Rock 'n' Roll Marathon.
"I was expecting it to be a fast race," said Koech, who also won the EDP Half Marathon in 59:54 in March and leads the Half-Marathon Grand Prix Series. "I am in great shape. After 10K I realized I was going to run a fast time."
Koech's time ranks fourth-fastest ever.
Running a 4:25 opening mile, the 25-year-old Kenyan broke away from countrymen Augustine Kipchoge and Stephen Kibet just after the 5-mile mark on an overcast day.
Kipchoge was second in 1:00:18 and Kibet third in 61:43. The trio, which broke from the rest of the elite field just after the 2-mile mark (8:58), hit 5 miles in 22:27 before Koech shook things up with a 4:23 sixth mile, which brought him through 10K unchallenged in 27:50. He continued to stretch out his lead from there, running 44:48 through 10 miles and covering the final 5K in 13:53.
Koech set a pending U.S. all-comers record for 10 miles with a time of 44:47. The previous record was 44:53 by Haile Gebrselassie in 2006. Race organizers said the 10-mile record meets the IAAF qualifications.
Two-time defending champion and San Diego resident Meb Keflezighi was the top American finisher in fourth place, running 62:11.
"I wish I had the opportunity to run this when I was in my prime running 1:01," said Keflezighi, who won the silver medal in the marathon at the 2004 Olympics. "But you know what, I'm still competitive, I still like to be there in the mix and the hometown crowd was phenomenal screaming, 'Go Meb! Go Meb!' I love racing in San Diego."
Simon Njoroge of Kenya won the marathon in 2:15:00. The women's winner was Natalia Sergeeva of Russia in 2:35:05.
Edna Kiplagat of Kenya won the women's half-marathon in 1:08:57.