South African swimmer Cameron van den Burgh broke his own 50metre breaststroke world record in the heats at the FINA World Championships.
Cameron van den Burgh put his 100metre breaststroke final disappointment at the FINA World Championships behind him with a world record in the 50m heats on Tuesday.
The South African led the 100m final for much of Monday's race before being overtaken by Great Britain's Adam Peaty.
But on his return to the pool in Kazan, Van den Burgh showed he will be a force to be reckoned with in the 50m competition, leading throughout and touching the wall in 26.62 seconds - 0.05secs quicker than his previous best.
Van den Burgh will return to action later on Tuesday as he looks to qualify for Wednesday's final.