Great Britain's world champion Adam Peaty has vowed to race faster in tonight's 50m breaststroke semi-finals at the World Championships in Kazan, Russia.

The 20-year-old, who won gold in the 100m breaststroke final on Monday, clocked 26.68s in the heats this morning.

Peaty's rival Cameron van der Burgh of South Africa equalled the Brit's unofficial world record of 26.62s in his respective heat.

"This morning I just went out there and had fun - I didn't really take it too seriously," Swimming.org quotes Peaty as saying.

"Tonight I'm going to come back and go faster. It'll be nice to get out there with my full game head on and focus on the race. I know I'm fully capable of going faster than my PB."

Last year, Peaty won four European gold medals and clinched two Commonwealth titles.