• Australia are relying on a Japan win against Saudi Arabia to help their chances of automatic World Cup Qualification (Getty Images)
The Socceroos head into their crunch qualifier with Thailand at Melbourne's AAMI Park knowing that whatever the result, they face an anxious wait afterwards.

A win or a draw will lift Australia into an automatic qualifying position.

But the Socceroos must wait until the early hours of Wednesday morning, when Saudi Arabia host Japan, to discover their World Cup fate.

Australia must better Saudi Arabia's result - or if they both win, produce a two-goal better win than the Saudis - to book their place in Russia.

Who the Socceroos could face in the World Cup play-offs
The Socceroos are holding onto hope of automatic qualification to the 2018 Russia World Cup ahead of their clash with Thailand on Tuesday.

It means Ange Postecoglou will have to turn their attention to the TV from 3:30am (AEST), barracking for Japan.

And if there's one more thing they know, it's that the Samurai Blue won't roll over.

"I don't think it's in their nature. It's not in their culture to not give 100 per cent," Socceroos captain Mark Milligan said, who spent two seasons in Japanese football.

Milos Degenek, the sole current Socceroo based in Japan, agreed.

"They always go 100 per cent into everything. They're never go half-hearted. They're not one of these countries that do other people favours. They're doing their own job," he said.

"Even if they play with a second string squad, they'll be doing their best to be in contention (to make the Japanese squad) for Russia.

"I don't think it's going to be an easy game for Saudi Arabia."

Japan, which sealed their place in Russia by beating Australia, have spared captain Makoto Hasebe and midfielder Shinji Kagawa the trip.

But their strong defensive form that suggests a fade-out isn't on the cards.

While Japan lost on their last trip to the Middle East - a 2-1 defeat to the UAE last September - they have conceded more than one goal in competitive matches against Asian opposition just three times this decade.

Whichever way it falls, the 10 hours between kickoff in Melbourne and the final whistle in Jeddah be pivotal in Australian football.

Japan forced to take cabs to training in Saudi Arabia
Japan's players had to scramble to training in taxis ahead of their World Cup qualifier against Saudi Arabia after their team bus failed to show up at their hotel.

Postecoglou is only focusing on the first 90 minutes.

"I spend zero hours thinking about things I can't control," he said.

"It's all about what we do on Tuesday night."