Australia’s Emma McKeon has swum a personal best on her way to a brave bronze medal in the 100-metres butterfly final at the Tokyo Olympics.

McKeon was aiming to become Australia’s first dual gold medallist of the Tokyo on Monday after scoring a win as part of the record-breaking 4×100-metre freestyle relay team on Sunday.

But it wasn’t to be. She swam a new national and Oceania record to be pipped for the silver medal by just 0.01sec.

Canada’s Margaret Macneil (55.59 seconds) set a Commonwealth record in taking the gold medal, with China’s Zhang Yufei in the silver spot.

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After the race, she put no limits on her potential Tokyo Olympics medal haul.

“To do a PB in an Olympic final, I’m pretty happy,” McKeon said.

“Really awesome.”

McKeon now has six Olympic medals, after winning four at the 2016 Rio Olympics.

Her butterfly bronze comes as part of a gruelling program in Tokyo that could still reap the Wollongong-born allrounder more Olympic gold.

She’s a genuine chance in both the individual 50-metre and 100-metre freestyles, with more medal opportunities in three more relays.

Coached by the renowned Michael Bohl, McKeon was Australia’s most successful athlete at the 2016 Rio Olympics, with a freestyle relay gold, two other relay silvers and a bronze in the 200-metre freestyle.

Fellow swimmer Ariarne Titmus could also add to Australia’s Olympic haul later on day three at the pool.

The 20-year-old Titmus, in the 400-metre freestyle final, takes on American megastar Katie Ledecky, the world’s best female swimmer.

Australia’s men’s 4×100-metre freestyle relay team is eyeing a medal but appears off the gold pace set by Italy and the US.

• See Australia’s full medal tally here

Elsewhere in the Olympic city, world No.1 tennis star Ash Barty, who suffered a stunning opening-round singles loss on Sunday, must regroup for the doubles.

Barty and Storm Sanders play China’s Yifan Xu and Zhaoxuan Yang in a second-round fixture.

The Hockeyroos also play China after starting their campaign with a win over Spain.

Likewise, the Stingers will aim to build on a first-up win against Canada when they take on the Netherlands in women’s water polo.

-with AAP