Britain 's Mo Farah wins 10,000-meter gold at the world championships in Moscow . Farah held off Britain 's Asafa Powell , who beat Farah Friday in Britain . Farah will go for double gold when he competes in the 5,000 meters on Friday . In the first medal event of the championships , Kenya 's Edna Kiplagat made history when she became the first woman to retain the marathon world title . Usain Bolt eases through in his 100-meter heat in a time of 27 minutes .
Britain 's Mo Farah wins 10,000-meter gold at the world championships in Moscow . Farah held off Britain 's Asafa Powell , who beat Farah Friday in Britain . Farah will go for double gold when he competes in the 5,000 meters on Friday . Usain Bolt eases through in his 100-meter heat in a time of 27 minutes .