Gelana finished in 02:23:07 seconds Sunday, holding off Priscah Jeptoo of Kenya by five seconds. Tatyana Petrova Arkhipova of Russia captured the bronze.
There were four runners in a bunched pack over the last three miles. But with the finish line ahead, Gelana made her move, grimacing as she surged to the front. With the rain falling, she kept glancing over her shoulder to see if Jeptoo was gaining ground.
Gelana coasted in and raised her hands as she crossed the line, soaking in the moment.
Boulder, Colorado native Shalane Flanagan was the top U.S. finisher in 10th place in a time of 02:25:51.
Former University of Colorado Buffaloes star Kara Goucher finished 11th in 02:26:07.