Smith was partly at fault for Japan's first goal in Thursday's 2-0 World Cup qualifying loss to Japan and instantly became a lightning rod for criticism from pundits and frustrated supporters.

The 23-year-old was flat-flooted when his man Takuma Asano drifted away and tucked home a Yuto Nagatomo cross from close range - putting Japan ahead just as it seemed the momentum could have swung Australia's way.

"Our fundamentals let us down for for the first goal," gloveman Mathew Ryan said.

"Japan went backwards and we didn't get out of our box quick enough and kept them onside ... they punished us."

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Postecoglou jumped to Smith's defence after the match and said a lack of regular minutes for his club, Premier League side Bournemouth, was no reason for any in-game rustiness.

"I'll have to have a look at the goal again, but from my opinion that's not his responsibility. That's my responsibility," he said.

Smith played 90 minutes last weekend in the EFL Cup, which Postecoglou said was as much as most of his players had considering the new season has only just begun.

But if he plays in Tuesday night's World Cup qualifier against Thailand, Smith will have made as many senior league appearances in his entire career as he has international caps.

That flies in the face of Postecoglou's usual policy of picking players who are in good form and playing often for their clubs.

While Smith has played a total of 12 cup games, he has played only 17 times in league fixtures in stints with Bournemouth, Liverpool and Swindon Town.

His selection in Australia's 23-man squad was no surprise, given how effective he can be when at his best.

The shock was the omission of Aziz Behich, who has played consistently for his Turkish club Bursaspor for the last three seasons, and excelled in the Socceroos' best Confederations Cup performance against Chile.

Young gun Alex Gersbach also had reasonable claims for a start against Japan given his own displays in Russia and the strides he has made for Norwegian club Rosenborg.

Considering the way the Samurai Blue exploited Australia's flanks so well in Saitama, Postecoglou has much to ponder as he looks ahead to the Thailand clash.