London, England –  With a little more than a kilometer to go in a rainy women's marathon, Ethiopian Tiki Gelana powered away from an elite lead group Sunday to earn the gold medal and set an Olympic record.

Gelana had been part of a four-woman group that also included Kenyans Priscah Jeptoo and Mary Jepkosgei Keitany and Russian Tatyana Petrova Arkhipova.

They were running together with 5 km to go, but as the race approached the final kilometer, Gelana pushed the pace and Keitany -- who has won the last two London Marathons and was a favorite heading into the race -- was the first to fall back.

Then, Arkhipova dropped off and Jeptoo was visibly struggling. Gelana, on the other hand, held her pace and crossed the finish line in 2 hours, 23 minutes and 7 seconds. That shaved seven seconds off the previous Olympic mark, set by Japan's Naoko Takahashi in 2000.

Jeptoo finished five seconds behind Gelana to take silver, while Arkhipova held on for bronze in 2:23:29.

Gelana's achievement was all the more remarkable because Sunday's race was conducted on wet roads and in frequent rain.

"As soon as the rain started, I said to myself, 'Thank God.' I love running in the rain," Gelana said. "I have been doing that since I was a small child. I slipped in the middle of the race and my elbow is still injured. But I didn't feel any pain during the race."

The 24-year-old, who won the Rotterdam marathon this year, became the first Ethiopian to win the women's Olympic marathon since Fatuma Roba in 1996.

"Fatuma is my hero," Gelana said. "I am extremely happy to share history with her. This gold medal is a gift for all Ethiopians."

Shalane Flanagan was the top American in Sunday's race, finishing 10th with a time of 2:25:51. Her training partner, Kara Goucher, was 11th. The third U.S. runner in the field, Desiree Davila, pulled out of the race because of an injury she has been struggling with recently.

"I could tell early on that it's not going to happen today," Davila, 29, said. "I will regroup and I am relatively young. I have a long career ahead of me. I don't want to compromise that."

The race began fairly slowly, with a half-marathon time of 1:13:13. That allowed a large lead pack to stay together.

But the shape of the marathon soon changed. Kenya's Edna Ngeringwony Kiplagat pushed the pace, taking Gelana, Keitany, Jeptoo, and Ethiopians Mare Dibaba and Aselefech Mergia with her.

That forced Flanagan and Goucher to chase. Flanagan latched back on, but only for a short time before falling behind again.

"The turns and the ups and downs were really, really hard," Flanagan said.

Arkhipova eventually bridged up to the leaders, while Dibaba couldn't stay with them.