Townsend, an Olympic gold medalist along with Roland Schoeman, Ryk Neethling and Lyndon Ferns in the 4 x 100 metres freestyle relay at the 2004 Olympics in Athens, Greece, clocked 1 min 42.01 secs, to dip inside Neethling previous national short course (25 metres swimming pool) best of 1:42.75 set in 2005.
He was equally as impressive in claiming three more gold medals - in the 100 metres freestyle (47.34), in the 100 metres individual medley (51.96) and in the 200 metres individual medley (1:52.89). His 100 metres individual medley effort was just outside of Neethling's national mark of 51.52.
"I really didn't expect to swim so fast in the 200 freestyle," said Townsend.
"I went in with the mindset that I was going to race the second seed guy in the first 100 metres and then try pull away from him in the second 100 metres, but when I saw the gap I had on him after 50 metres already, I decided to go for it.
"I was still very shocked to see the time at the end. It goes to show it happens when you least expect.
"The individual medley was almost straight after the 200 freestyle, but I made the most of the time I had between the two events to eat a little and warm down. There was no one close to me in the actual race so I am pleased with the time considering I was alone at the front. It is also nice to dip under the 1:53 barrier again, something I haven't done since the World Cup in Berlin last year."
Townsend, who won gold in the 200 metres individual medley and silver in the 100 metres individual medley in the opening leg of the FINA/Arena Swimming World Cup circuit in Durban last month, will take to the water in the two-day showpiece event in Moscow in the 100 and 200 metres individual medley, and 100 and 200 metres freestyle races.