Midfielder Massimo Luongo is forecasting an early assault as the Socceroos attempt to unlock a stodgy Saudi Arabia in Thursday's vital World Cup qualifier.

Luongo believes the Saudis, who hold a three-point buffer from the Socceroos in group standings, may play for a draw in the Adelaide Oval fixture.

"A goal early would ruin their game plan and they'll be forced to come out and try and score, and that will help us," Luongo said on Sunday.

The Saudis are equal on points with leaders Japan, with three group games remaining.

The top two secure spots for next year's World Cup in Russia, while the third-placed nation is pitched into play-off rounds.

Both Australia and Saudi Arabia also play Japan in the remaining rounds, meaning Thursday night's match is crucial to direct passage to Russia.

Luongo said the group standings would "probably" lead to the Saudis adopting time-wasting tactics in Adelaide.

"To be fair, in the previous games the refs have been quite good at handling all that," he said.

"But we're going to get all that, or they are going to try and interrupt our momentum and flow.

"A draw might be good enough [for the Saudis] but if we get a goal, or when we get a goal, it's just going to unlock them.

"They they'll need to come out and play . . . so I think that will benefit us even more.

"And we have practised against teams sitting off and trying to cause us not to score or to disrupt us and we have done pretty well so far."

Luongo arrived in Adelaide content with his output for Queens Park Rangers in the English Championship, but mindful of his challenge to seal a midfield spot in Ange Postecoglou's starting line-up.

"We have got loads of depth in there, it causes Ange a problem but it's not the worst problem in the world to have," he said.

"It adds that bit of competition in training and it pushes everyone a little bit more.

"I know that I have got to be on the top of my game in training, otherwise I know these other boys will grasp it."

Meanwhile, goalkeeper Mat Ryan is feeling the heat to keep his Socceroos spot – and he doesn't want it any other way.

Ryan says he's the perfect example of the burgeoning depth in the 23-man squad for the big match against Saudi Arabia.

Ryan started in Australia's 2-2 draw against United Arab Emirates in March but his rival Mitch Langerak got the nod for the previous fixture against Iraq.

And Ryan says he's relishing his personal duel with Langerak, who was in stunning form for German club Stuttgart, playing every minute of their league campaign to help earn promotion to the top-flight Bundesliga.

"It has been great for the squad that a number of guys have been successful at their clubs," Ryan said on Sunday.

"It's a real positive reflection of being an Australian . . . it's in our DNA and that is exactly what we strive for.

"There is always an increase in the number of guys heading overseas and getting deals and playing well and winning trophies and it's only going to complement us as a team.

"The depth in the squad at the moment is very strong."

Ryan, who returned to form during his stint on loan to Belgium's Racing Genk from his Spanish club Valencia, said the squeeze for spots was exactly what Postecoglou wanted.

"He doesn't want any player being relaxed in their position. The positions are always up for grabs, and that is how it should be in a national team," Ryan said.

"At the end of the day, the best man has got to win the spot. Individually it can be disappointing if you miss out but we all put that behind us for the best of the team, I can honestly say we're a really good group for that.

"But it just makes us work even harder. I'm an example of that. My spot is not guaranteed either. So I'm doing the best I can to win that spot on Thursday night."

AAP