BOSTON — The Kenyans are back in Boston after a relative lull that saw them shut out in the world’s most prestigious marathon twice in the past three years.

More surprisingly, so are the Americans.

Geoffrey Kirui won the 121st Boston Marathon on Monday, pulling away from three-time U.S. Olympian Galen Rupp with two miles to go to give Kenya its first men’s victory in five years. Edna Kiplagat won the women’s race to complete the Kenyan sweep.

They were followed closely by Americans who grabbed two of the top four women’s spots and six of the top ten for men — the first time that’s happened since the race went professional in 1986.

“It’s so exciting to see Americans being competitive here,” said Rupp, the Olympic bronze medalist who was making his Boston debut. “It’s a real exciting time. And it’s awesome to see American distance running on the upswing and being competitive in these races.”

Kirui finished in 2 hours, 9 minutes, 37 seconds to claim a silver trophy, a guilded olive wreath from Marathon, Greece, and the $150,000 first prize. Rupp was 21 seconds back, and Japan’s Suguru Osako 30 seconds behind him.

Rounding out the top 10 were runners from California, Arizona, Colorado, Oregon and Utah.

“American distance running is looking good today,” said sixth-place finisher Abdi Abdirahman, a Somali immigrant and Tucson resident who is a four-time Olympian. “We have the podium for both men and women, so the future is great.”