BOSTON (AP) -- The pace was slower than most years, but the finish of the Boston Marathon's women's race was as gripping as ever.

Sharon Cherop outlasted hot weather, a sore knee and a sprint to the finish to beat fellow Kenyan Jemima Jelagat Sumgong in yet another women's race that wasn't decided until a dash in the final yards.

Cherop finished in 2 hours, 31 minutes, 50 seconds, two seconds ahead of Sumgong. It was the fifth straight year the women's race was decided by three seconds or less.

"I'm so happy because it's my second time being here in Boston," she said. "This time around I was really prepared."

With temperatures rising to 78 degrees by the finish, Cherop won with the second slowest time in Boston since 1985. But it was her speed at the end that sealed it.

Cherop broke away in the final stretch down Boylston Street, and it briefly looked like she might have made her move too soon. Sumgong closed the gap, but couldn't overtake her.

Cherop said when she rounded the last turn next to her friend and fellow Kenyan, her plan was to speed up with about 600 meters to go, then again at 300 meters.

"I know how she runs," Cherop said.

Sumgong said she and Cherop had been running at a "comfortable pace," and she didn't think the race was over, even when Cherop first pulled away.

"I was thinking, maybe I would catch her," she said. "But she kept on pushing, pushing, pushing."

Another Kenyan, Georgina Rono, finished third at 2 hours, 33 minutes, 9 seconds.

Cherop, 28, is the third Kenyan in five years to win in Boston.

Cherop finished third last year, six seconds behind winner Caroline Kilel of Kenya after she couldn't keep pace during the final push. Cherop said she didn't know when the finish line was coming last year, so this year she trained for the course and was ready.

Cherop was nursing a sore right knee at the start of the race, but the hot weather turned out to be a bit of a break because it slowed the initial pace.

"I was not 100 percent," Cherop said. "That is why the slow race was good. It helped me see how my knee was feeling."

Sumgong, meanwhile, said the conditions were completely new to her.

"The heat affects us a lot," she said. "I have never run in very hot and humid places."

Cherop and Sumgong ran with the leaders until Cherop took the lead at about mile 18. The two then ran even for the final few miles before Cherop took the lead at the very end.

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