By Scott Malone and Tim McLaughlin
BOSTON (Reuters) - Ethiopia's Lelisa Desisa and Kenya's Rita Jeptoo won the men's and women's Boston Marathon on Monday, continuing African runners' dominance in the sport.
The results underlined both the strength and rivalry of those two nations' running programs, said Kenyan runner Wesley Korir, who finished fifth.
"It was more of a tactical race, the Ethiopians versus the Kenyans," said Korir, who won the 2012 Boston Marathon. "Those guys were not fighting for time or anything, they were just racing to beat each other."
Desisa finished in an official two hours, 10 minutes and 22 seconds, besting countryman Gebregziabher Gebremariam and Kenya's Micah Kogo in a finishing sprint.
Jeptoo closed up in an official two hours, 26 minutes and 25 seconds, crossing the finish line more than 30 seconds ahead of her nearest challenger, Meseret Hailu of Ethiopia.
Americans took fourth place in both races, with Jason Hartmann and Shalane Flanagan finishing just off the podium. No American has won since Lisa Larsen-Weidenbach in 1985.
Hartmann, who also placed fourth in last year's race, took an early lead before being reeled in by a large pack of runners at the halfway mark.
After that he held back and did not try to match every move of the leaders, he said.
"The last five miles is where you can determine whether you run good or not," Hartmann said.
At 23 years old, Desisa is a relative newcomer to the sport, though earlier this year he won the Dubai marathon in a time almost six minutes faster than Monday's pace, which stands as his personal best.
Jeptoo, Hailu and third place women's finisher Sharon Cherup of Kenya ran a carefully paced race, holding back for most of the 26.2 miles as first Colombia's Yolanda Caballero and later Portugal's Ana Dulce Felix took early leads.
Felix pushed as far as 90 seconds ahead of most of the top women before Jeptoo and other chasers ran her down in the 24th mile of the 117th running of the race.
Jeptoo's victory marked her second win at Boston. Her first came in 2006 -- a race she almost missed the start of due to passport problems.
(Editing by Frank Pingue)