Ethiopian runner Lemi Berhanu Hayle won the men's race after breaking away from defending champion Lelisa Desisa. Hayle won in 2 hours, 12 minutes and 45 seconds. It's the first time Ethiopian runners have swept the elite men's and women's titles and the first sweep for a country since Kenya took both crowns in 2012.
Hayle and Desisa were alone in front by the halfway point, en route to a sweep for Ethiopia in the men's division.
Hayle crossed the finish line 47 seconds ahead of Desisa (2:13:32). Yemane Adhane Tsegay rounded out the sweep in third place (2:14:02).
In the women's race, Baysa finished in 2:29:19 for her first Boston title despite trailing by 37 seconds in the hills outside the city. Tirfi Tsegaye of Ethiopia was second (2:30:03) and Joyce Chepkirui of Kenya took third (2:30:50).
Tsegaye and Chepkirui were side-by-side with Baysa nowhere in sight before making her move. Baysa had caught up to the leaders with about three miles to go, then continued pulling away all the way to the finish on Boylston Street.
Defending champion Caroline Rotich dropped out of the race after about five miles. Neely Spence Gracey was the top American, finishing ninth (2:35:00) in her first marathon. Gracey, 26, was making her debut in the event her father, 1990 champion Steve Spence, won the day she was born.
Hayle finished only a few minutes behind the women's leaders after breaking free of Desisa in the final mile. Hayle had to pause during a post-race interview, tearing up with emotion after winning his first major marathon. He and Desisa were running side-by-side after breaking away early and stayed that way almost to the end of the 26.2 miles.
Hayle had the better kick down Boylston Street to finally break free of Desisa as he fell short of becoming the first defending champion to repeat in the Boston Marathon since Robert Kipokoek of Kenya won three straight (2006-08).
Desisa added a second-place finish to the titles he won last year and in 2013.
Zachary Hine of Dallas finished 10th (2:21:37) and was the top American in the men's field.