McKeon stormed to the finish, stopping the clock in 56.18, finishing behind Rio de Janeiro Olympics gold medallist Sarah Sjostrom.

It bettered Jessica Schipper’s previous Commonwealth record of 56.23, which McKeon had equalled to qualify for the final in Budapest. 

“That was so good, I’m just glad I could get faster each heat, semi and then final, and do a PB and nearly dip under that 56,” McKeon said.

McKeon had turned third, but surged over the top of American Kelsi Worrell, who took bronze in 56.37.

Still half-a-second behind Sweden’s Sjostrom, McKeon said she is relishing the challenge of closing the gap. 

“You want to have tough people in your event,” she said. 

“Because it lifts you and it makes you push harder and train harder, and you want to be up with them, so it’s a good thing I think.”

McKeon was Australia’s most successful athlete at the Rio Games, finishing with four medals, including a relay gold medal and world record.

At the Olympics, McKeon finished seventh in the 100m butterfly final in 57.05, won by Sjostrom in 55.48.

Returning to the pool on Wednesday for the 200m freestyle heads –the event she won bronze in Rio – McKeon said adding the 200m butterfly to her already packed program had paid dividends.

“Doing those 200flys has definitely helped my backend,” McKeon said.

“Last night I did half a second quicker on my backend than I’ve ever done before so, yeah it’s definitely helped, even though it is a long way doing butterfly.” 

McKeon was the Illawarra Mercury’s sportsperson of the year award in 2014 and 2016.