UPDATE 1-Athletics-Britain's Johnson-Thompson leads heptathlon after four events

Britain's Katarina Johnson-Thompson produced two personal bests as she made a superb start to the heptathlon at the world athletics championships on Wednesday, opening a 96-point lead over defending champion Nafissatou Thiam after four events. The 26-year-old Johnson-Thompson took an early lead after running a lifetime best of 13.09 seconds in the 100m hurdles, before matching Thiam with a clearance of 1.95m in the high jump.

The Belgian briefly reclaimed top spot with a 15.22-metre throw in the shot put, but Johnson-Thompson kept in touch with a personal best of 13.86 metres. The Briton then retook the lead with a season's best of 23.08 seconds in the 200 metres to move onto 4,138 points and put herself in a position to win her country's second gold of the championships. Britain clinched its first gold when Dina Asher-Smith dominated the 200 metres final on Wednesday at the Khalifa International Stadium.

"Gold - why not?" Johnson-Thompson said. "I am in shape and in the position to do it but you never know what can happen on day two." Thiam trails Johnson-Thompson with 4042 points but was nonetheless pleased with her performance with three remaining events on Thursday -- the long jump, the javelin and the 800m.

"I'm happy with what I did today and I hope I can be good like that tomorrow and see what happens," Thiam said. Kendell Williams of the United States sits in third with 3,855 points.