Cape Town - South Africa's star swimmer Chad le Clos has qualified fourth-fastest for the final of the men's 100m butterfly at the FINA World Championships in Gwangju, South Korea.

Swimming in the first semi-final out of Lane 5, Le Clos touched the wall in a time of 51.40, behind Hungarian teenager Kristof Milak (50.95).

When all was said and done, Le Clos wound up with the fourth fastest overall time.

The timesheets were led by American superstar Caeleb Dressel who obliterated compatriot Michael Phelps' 10-year-old world record (49.82) when touching the wall in 49.50.

Le Clos took the bronze medal in the 200m butterfly, but scratched from his other two events - the 50m butterfly and the 100m freestyle.