Long-distance legend Haile Gebrselassie broke the world half-marathon record by a remarkable 21 seconds in Arizona.
The 32-year-old Ethiopian clocked a time of 58 minutes 55 seconds running the second half of the Rock 'N' Roll Arizona marathon.
Gebrselassie, twice Olympic 10,000m champion, also broke the 20km record en route, the 20th time in his career he has set a world mark.
"These are my first in America," he said. "It's a little special to me."
While nearly 34,000 took part in the marathon and related running events on Sunday, only Gebrselassie and four pacesetters took off from the midpoint of the marathon course.
"You can see from today's record. I hope I will do very good in the London Marathon"
His half-marathon time broke the mark set by 18-year-old Kenyan Samuel Wanjiru last September.
Gebrselassie's 20km time wiped out the record clocked by his long-time rival Paul Tergat of Kenya in 1998.
The Ethiopian won Olympic gold at 10,000m in 1996 and 2000 but has now turned his attentions to the roads where he hopes to add to his medal collection at the 2008 Games in Beijing.
As part of his preparation, he will take part in the London Marathon in April but although he has targetted Tergat's world marathon record, he played down his chances of breaking it in the English capital.
"You can see from today's record. I hope I will do very good in the London Marathon," he said.
"If I do not break the world record but win in London, it is something special. But we'll see. Anything is possible."