Jet-lagged and lethargic, veteran Roland Schoeman still blew away the competition to win the 50m butterfly at the SA championships in Durban last night.

His 23.69sec winning time gave him victory by more than half-a-second, although it was slow by his own high standards.

"I haven't done too much fly training this year," said Schoeman, 34, who is competing at his 18th national championships.

Swimming SA has said that swimmers cannot qualify for the world championships in Russia later this year in non-Olympic events. That leaves Schoeman with two options - the 100m and 50m freestyle races.

"I got in three days before the competition which was not ideal, but my coach and I decided we wanted [to compete] to get used to the World Cups [a swimming series later in the year], " Schoeman said.

Chad le Clos, who opted not to swim the 50m fly this year, was the only swimmer on the night to post a qualifying time for the world championships, clocking 1:47.93 in the 200m freestyle semifinals.

Cameron van der Burgh won the 100m breaststroke in 59.78sec.