Australia's hopes of automatic qualification are in the balance but Mark Milligan believes there is no doubt they will be at their fifth consecutive World Cup.
Last week's 2-0 loss to Japan means the Socceroos are no longer in control of their qualifying hopes and face a high-pressure encounter against Thailand in Melbourne on Tuesday.
The green-and-gold are level with Saudi Arabia on 16 points but sit in third position on the table because of goal difference.
To qualify automatically and avoid the playoff route, Australia must better the result of the Saudis, who play Japan in Jeddah on Wednesday (AEST), or make up the +2 goal difference advantage if both teams win.
Milligan acknowledged the complexities of the Socceroos' path to Russia but is confident qualification will be achieved one way or another.
"Whether it's Wednesday that it's announced that we're going to a World Cup or whether we have to wait a bit longer, it will happen," the midfielder said.
Game day. Tonight, it's all on the line. Let's do this.
📍: Melbourne Rectangular Stadium
🕗: 8.00pm AEST
📺: Fox Sports 505 / 9Go!#AUSvTHA pic.twitter.com/QHetXFj8Am — Caltex Socceroos (@Socceroos) September 4, 2017
"Obviously that's worst case scenario but there's a long way before we have to hit that panic button.
"I still truly believe that we will go out Tuesday night and we'll put in a good performance.
"Going to consecutive World Cups has been very important not just for the national team but for Australian football, the A-League and lower leagues."
If Australia are forced into the playoffs, they will face a two-leg tie against third position in group A (currently Syria), before facing fourth place in CONCACAF qualifying (currently Honduras) home-and-away to book a spot at next year's tournament.