Barcelona - Gerhard Zandberg will join medal hopes Roland Schoeman and Chad le Clos in Saturday evening's session at the 15th FINA world championships in Barcelona.
Zandberg, who has been on the 50m backstroke podium in four out of the five last competitions, missing out only in 2005 when he did not compete, swam a 24.85 to qualify with the fourth-fastest time.
He will swim in the semi-finals in the Palau Sant Jordi on Saturday evening, while le Clos will be in action in the 100m butterfly finals and Schoeman in the 50m freestyle finals.
The 2007 champion Zandberg said he was happy with his time.
"My plan was to just swim it and not sprint it, that’s for tonight," Zanberg said.
"I am seated very nicely for the semi-final and it feels very comfortable swimming at high velocity again."
The three fastest qualifiers for the semi-final are Daniel Orzechowski of Brazil, Spain’s Aschwin Wildeboer and Jeremy Stravius of France.
Le Clos will battle birthday boy Ryan Lochte for the men's 100m butterfly gold later on Saturday, while veteran sprinter Roland Schoeman set back the clock as he qualified for the 50m freestyle final.
There was less success for the other South African swimmers involved in the heats on Saturday morning as Myles Brown, Trudi Maree and Tara-Lynn Nicholas failed to advance in their respective events.
Brown who swam the longest pool event on offer, the 1 500m freestyle, finished in a time of 15:14.51 to place 17th.
The distance pool swimmer who made the final of the 400m freestyle on the first day of competition and finished 6th was pleased with his swim.
"I swam PB’s (personal bests) in all my races at my first world championships so I’m very happy," Brown said.
"Everyone is so professional here and I have learnt a lot from the top distance guys, so now I just have to take it home and work on it in practise."
Maree, 25, finished in 33rd place of the women’s 50m freestyle in a time of 26.02.
"I have no idea what went wrong there. I had a terrible race and was very shocked when I saw the time."
The fastest qualifiers for the semi-final were the Malawian-born Campbell sisters, who lives in and swim for Australia, with Cate placing first and Bronte third, while Francesca Halsall of Great Britain had the second-fastest time.
Nicholas, meanwhile, swam a time of 33.04 to finish 45th in the 50m breaststroke.
Russian swimmer Yuliya Efimova, who broke Jessica Hardy's 2009 world record by 0.02 seconds in the heats, led the qualifiers in 29.78.