Zersenay's first road race of 2010 was the Lisbon Half Marathon. The organisers had modified the course and assembled a field of fast runners in order to facilitate a quick race. Despite the top five athletes all running personal best times, Zersenay was alone at the very front from 10 km onwards. He fell four seconds short of the 15 km world record, but significantly revised Haile Gebrselassie's four-year-old 20 km world mark to 55:21, beating it by almost half a minute. Samuel Wanjiru's half marathon world record was next to fall as Zersenay crossed the line at 58:23 minutes, a clear ten seconds ahead of the previous mark.