When Marnus Labuschagne got his big Ashes break at Lords last August as Test cricket’s first concussion substitute, he could never have imagined that within five months he’d be knocking on the door of matching Steve Smith’s batting average.

Labuschagne will resume at the SCG Saturday on 130 on day two of the third Test against New Zealand with the Australians at 3-283.

It was his fourth ton of the home summer – and if the right-hander finishes unbeaten this innings he needs only five more runs to overtake Smith’s average of 62.84, while 68 more runs will ensure he rises above that mark if dismissed.

Smith’s numbers come from 131 innings, while Labuschagne is in the midst of his 22nd knock.

Nonetheless, on Friday it was clear the apprentice was scoring with far more ease than the master during a 156-run partnership between Labuschagne and Smith (63).

“I don’t think it’s even a comparison,” Labuschagne told reporters.

He’s been doing it for a long time and his consistency is amazing … it’s something I aspire to. I want to be as consistent as Steve.

“For one person to perform for over a summer – or over a year – to compare that to a guy who has been performing for eight years (is wrong). It can turn very quickly.”

Labuschagne has already helped himself to 752 Test runs this seasons, while he became the 10th Australian to post four tons in a home summer.

Smith, Sir Don Bradman and Neil Harvey are the only Australians to have scored more runs in a home summer of five or fewer Tests.

Steve Smith took 39 minutes and 45 balls to get off the mark on day one. Photo: AAP

The 25-year-old, who rocketed from 110th to fourth in the ICC’s Test batting charts during 2019, suggested Smith and David Warner’s return from a year-long suspension helped fuel his rapid rise.

“You want to soak it all up because they’ve got so much knowledge … not just in Test cricket but all cricket,” Labuschagne said.

“They play all three formats. You might be doing alright in one format but they’re doing alright in three formats.”

Labuschagne is set to make his ODI debut later this month in India.

Smith and Labuschagne’s contrasting battle was perhaps best depicted by a quick single the veteran batsman took to get off the mark, having faced 45 balls without scoring.

“I actually had no idea he was on zero until the 38th ball. I thought we were rotating the strike well,” Labuschagne laughed.

“I was like ‘what’s the carry on for?’. There was a lot of (crowd) noise.

“He was like ‘I’m on zero’.

“They’ve come at the best batter in the world in a different way … he is still countering it, still putting runs on the board. It’s just testament to him as a player.”

-with AAP