BOSTON — The runners were soaked, the pavement slippery, and Robert Cheruiyot knew exactly where trouble was waiting along the Boston Marathon route.

So 48 hours before the start of yesterday’s race, after his more traditional training was complete, the defending champion headed to the course to test the traction of the finish line. It was at the end of the Chicago race, 26 miles and 384 yards in, that he slipped — nearly costing himself a race, if not a career.

“I don’t want myself to think about falling down in Chicago,” Cheruiyot said after overcoming from a concussion from that slip and the remnants of a nor’easter to win his third Boston title. “It is like telling someone something very bad. … It is not good.”

Cheruiyot, who also won in 2003, earned his third Boston title standing up. He outkicked countryman James Kwambai on the way into Kenmore Square to win in 2 hours, 14 minutes, 13 seconds — slower than the course record of 2:07:14 he set last year but enough to win by 20 seconds.

“When the lion is chasing the antelope, he doesn’t look back. He has to eat,” Cheruiyot said. “So when I run, I don’t stare at my time.”

Kenya took the top four spots in the men’s race and its 15th victory in 17 years. The top American man was Peter Gilmore, in eighth place.

Russia’s Lidiya Grigoryeva captured the women’s crown in 2:29:18, winning by 20 seconds and sending Latvia’s Jelena Prokocuka to her second consecutive second-place finish. Grigoryeva, who set the course record in Los Angeles last year, veered to the stands to grab a Russian flag just before crossing the finish line.

Top American hope Deena Kastor fell back after stomach problems diverted her from the course for a minute near the midpoint. Kastor, the defending London champion, American record-holder and Olympic bronze medalist, still finished first in the U.S. national championships, a race within a race that carried a $25,000 bonus.