SAPPORO (REUTERS) - Kenya's Peres Jepchirchir won the Olympic women's marathon in Sapporo on Saturday (Aug 7), outduelling compatriot Brigid Kosgei in the final minutes and claiming her country's second consecutive gold medal in the event.

Kosgei took silver and Molly Seidel of the United States, competing in just her third marathon after moving up from shorter distances, claimed the bronze.

Kenyans Kosgei, the world record holder, and world champion Ruth Chepngetich had been the favourites to win the gold.

But it was two-time world half-marathon champion Jepchirchir who came out on top after breaking out of a virtual tie with Kosgei at the 40km mark where she decided to make her move.

"When I was there I said, 'Wow, I'm going to make it.' So I pushed the pace because I knew I was going to win," Jepchirchir said.

"I'm so, so happy because we win as Kenya, first and second ... I'm happy, for my family, happy for my country Kenya for supporting us."

She finished in 2hr 27min 20sec, 16 seconds ahead of Kosgei and 26 seconds in front of Seidel.

Battling hot and humid conditions, Chepngetich dropped out around the 30km mark, while Israel's Lonah Chemtai Salpeter dropped out at the 38km stage after looking like a strong contender for bronze.

The race was moved to Sapporo from Tokyo ahead of the Games in an effort to beat the sweltering summer heat in the Japanese capital. But a heat wave has been sweeping the area, and even after rescheduling the race to begin an hour earlier at 6am, temperatures had climbed from 26 deg C at the start of the race to 30 deg C by 9am.

Sally Kipyego of the United States, who was with the leader's pack at the midway point but finished more than five minutes off the lead, said the heat was "absolutely" a factor.

"I knew that I was really fit coming in, so that performance is nowhere close to my fitness. I know the heat had to play a role and I just thought I was going to cope better and I didn't," she said.