Paula Radcliffe clocked the second fastest time ever to retain the world women's half-marathon title in Bristol today.
Radcliffe, the world long-distance cross country champion, took off on her own after 15k of the 21.1-k race to clock one hour six minutes 47 seconds in cold, windy conditions.
Japanese Yasuyo Iwamoto and Mizuki Noguchi made the early pace in a leading bunch of 13 with Radcliffe in third place.
Radcliffe led through the first loop of the course before pouring on the pace in the second half.
She dropped Ethiopia world 10,000 metres silver medallist Berhane Adere and the race developed into an gripping battle between herself and Chepkemei.
Radcliffe lifted the pace again and this time Chepkemei was unable to respond, gradually falling behind.
As the field approached the city centre for the last time, Radcliffe drove on, finishing 49 seconds clear of Chepkemei with Adere third in 1:08:17.