Adam Gemili has become the second fastest Briton of all time over 200m by registering a time of 19.98 seconds to win his semi-final at the World Athletics Championships in Russia.

The 19-year-old Londoner, who alongside Usain Bolt is now one of the favourites to win the event that concludes on Saturday, admits that he did not expect to run so fast.

"I can't believe it," he told BBC Sport. "Honestly, that's the best feeling in the world. To beat 20 seconds - I'm over the moon. I didn't realise the time was me - I didn't know if I'd qualified. I've made the final, I've run a PB, and I'm so grateful.

"But I've still got the final, so must get back and get some rest. I'm happy with that performance, so whatever happens now.

"I've put myself in with some of the fastest men in the world. Crazy. Crazy, crazy, crazy. I'm speechless."

Gemili's previous personal best was the 20.17-second run, which saw him win his first-round heat earlier on Friday.

John Regis holds the British record over 200m. He ran 19.87 seconds in Sestriere, Italy, in July 1994.