Arch rivals Matt Shirvington and Patrick Johnson moved a step closer to a classic men's 100m final by clocking identical heat times at the Australian track and field championships.

Running in the first heat, the in-form Johnson clocked 10.26 seconds and then declared himself the underdog, despite beating Shirvington in all but one of their previous races this year.

A couple of minutes later, five-time defending champion Shirvington ran exactly the same time.

In other action on day one of the championships, leading ladies Cathy Freeman (400m) and Jana Pittman (400m hurdles) ran moderate heat times but still qualified with ease in their respective events.

Pittman is a real medal hope for the world championships in August, but Olympic long jump silver medallist Jai Taurima almost certainly won't even be going to Paris after reinjuring his left ankle during qualifying.

But the highlight of Friday's packed program at ANZ Stadium will be the men's 100m final.

"That was pretty cruisy, just nice and relaxed," said Johnson after dominating the opening 100m heat.

"Matt's the favourite, I'm the underdog and I like the underdog stature. He's the national title record holder."

When asked what chance there was of a really fast time in the final, Johnson replied: "If it's hot, we'll see what happens. It'll be fun."

What an ultra focused Shirvington thought about being labelled the underdog couldn't be ascertained as he declined to speak to the media after powering through the second heat.

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