Kimetto broke the course mark Sunday in capturing the Chicago Marathon, and compatriot Rita Jeptoo was the women's winner in the first major marathon in the United States since the Boston bombings.
Kimetto finished in 2 hours, 3 minutes, 45 seconds, leading a 1-2-3 finish for Kenyan men. He beat the mark of 2:04:38 set by Ethiopia's Tsegaye Kebede last year. He pulled away from Emannuel Mutai over the last few miles and was all alone with both arms raised as he crossed the finish line.
It was his second major victory this year to go with a win at Tokyo in February — not bad for someone who was tending corn and cattle in the west Kenyan town of Eldoret.
He said through an interpreter that he had been running on his own when he had a chance meeting with Geoffrey Mutai. A star marathon runner and fellow Kenyan, Mutai asked Kimetto to join his camp near Eldoret and train with him.
Kimetto finished second in his marathon debut in Berlin last year, won Tokyo and added to his status as one of the world's best on Sunday.
Before the race, there was a 30-second moment of silence to honour the victims of the Boston bombings.
Mutai (2:03:52), the 2011 London winner, also beat Kebede's time but finished seven seconds off the lead. Sammy Kitwara (2:05:16) was third.
Jeptoo followed up her victory at Boston by easily taking the women's race, finishing in 2:19:57 after losing in a sprint a year ago. There was no one near Jeptoo as she turned into Grant Park, wearing a wide grin and waving to the crowd.
Jemima Sumgong Jelegat of Kenya (2:20:48) was second, followed by Maria Konovalova of Russia (2:22:46).
The winners each earned $100,000. Kimetto gets an additional $75,000 for the course record, while Jeptoo gets another $40,000 for finishing under 2:20:00.
On a sunny day with the forecast calling for temperatures to hit the high 50s when the top runners finished, conditions were close to ideal. But there was a different feel to this event in the wake of the Boston Marathon bombings, which killed three people and injured more than 260 others.
Police promised heightened security. More than a thousand uniformed and undercover officers and more bomb-sniffing dogs mixed with the crowd along a course winding through 29 neighbourhoods. Officers inside a command post monitored pictures coming in from helicopters and the city's 22,000 cameras, the most extensive surveillance system in the nation.
The Department of Homeland Security designated the marathon a "level two" event, a notch below massive gatherings such as the Super Bowl, which meant more federal agents with their own high-tech monitoring equipment.
Runners also saw changes.
They only used clear plastic bags issued by organizers to store their belongings near the finish line. They had to pick up their own packets, with race bibs and tracking devices, rather than friends or family.
"I thought everything went really, really smooth," executive race director Carey Pinkowski said. "I think the key to that was the messaging to our participants, to our volunteers. We asked our participants to get there a little bit earlier. I think everything went well."
Ernst Van Dyk of South Africa won the men's wheelchair division race in 1:30:37. Tatyana McFadden of Champaign, Ill., won the women's division in a course record 1:42:35.
McFadden, who also won the Boston and London marathons this year, will attempt a Grand Slam in wheelchair racing at the New York City Marathon next month.
The 29-year-old Kimetto and Mutai started to surge ahead around the 19th mile, only to have fellow Kenyans Sammy Kitwara and Micah Kogo stayed with them. Those two faded after the group passed through Chinatown.
The gap between Kimetto and Mutai started to widen after Mutai missed his bottle at a water station around the 24-mile mark, although Mutai said that was a non-issue. Kimetto wasn't aware it happened.
Either way, he took control over the last few miles. The world record of 2:03:23 was in sight, set by Wilson Kipsang of Kenya in Berlin two weeks ago. But Kimetto settled for the course mark. He had no problem with that, particularly considering he was about six weeks removed from a bout of malaria.
The 32-year-old Jeptoo had an easier finish. Last year, she traded leads with Atsede Baysa of Ethiopia down the stretch and lost a step. Six months later, Jeptoo won her second Boston Marathon, a victory that was overshadowed by tragedy.
This time, she had a big smile and waved to the crowd on her way to the finish line.
"In 2006, I won in Boston and after that, I (did not) do well," Jeptoo said. "Last year and this year, I'm really doing well. When I ran Boston again, I saw my dream is coming. This is my happiness."