by only Paul Tergat. Half marathon world record 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. He managed to finish his first full-marathon at the 2010 London Marathon, although his time of 2:12:03 for seventh place was not as strong a transition as expected. He made his first appearance at the Giro di Castelbuono in Sicily in July and, although he described the course as "very hard", he won the race ahead of Samuel Wanjiru. He attempted for yet another title at the 2010 IAAF World Half Marathon Championships, but Wilson Kiprop brought an end to his four-year reign – the Eritrean took the silver medal, labouring towards the end and pulling up in injured at the line. He was still suffering from the injury at the San Silvestre Vallecana some two months later, although he managed to beat Ayad Lamdassem to win the race. He was at full strength at the 2011 Lisbon Half Marathon: he missed his world record mark but ran the second fastest of all-time (58:30 minutes). In the outdoor track season he ran 26:51.09 minutes for the 10,000 m at the Prefontaine Classic and came close to a personal best with a win at the Barcelona Meeting with a time of 12:59.32 minutes. Making his fourth consecutive appearance in the event, he took fourth place in the men's 10,000 m at the 2011 World Championships in Athletics. He ended the year with road wins at the Porto Half Marathon and the São Silvestre de Luanda, setting course records of 59:30 minutes and 27:44 minutes, respectively. At the 2012 World's Best 10K he came third, beaten by Sammy Kitwara and Vincent Chepkok. He won the Lisbon Half Marathon for the third straight year, but was slower than previous times (59:34) due to warm conditions and