The tension around automatic World Cup qualification cranks up a few more notches on Tuesday night when AFC's Group B comes to a climactic end in Melbourne and Jeddah.
SUMMARY
Australia host Thailand in Melbourne, while Saudi Arabia are at home to the already qualified Japan in the final game of Group B.
The final matchday in the third round of qualification for 2018 FIFA World Cup always carries the possibility of tension, twists and turns.
There should be plenty of all that in evidence on Tuesday in Melbourne and later in Jeddah.
As things stand Thailand has just two points from nine games but the focus is not at the bottom of Group B. It is on which two teams will automatically qualify for Russia 2018.
REPORT: Caltex Socceroos beaten in Saitama
Saudi Arabia's shock loss in UAE
SITUATION AFTER THIS WEEK'S MATCHES
Japan's 2-0 win over the Caltex Socceroos last Thursday in Saitama leaves Australia in a tricky situation.
The three points that Japan collected took the team to a sixth successive World Cup and it also leaves just one automatic spot for either Saudi Arabia and Australia.
Both teams have 16 points but Saudi Arabia has a goal difference advantage of two and has also scored two more goals.
This is deficit that Australia has to overcome.
If the two teams get the same result by the same margin then the West Asian team will take second.
That's the bad news.
JAPAN CAN STILL DO US A FAVOUR
The good news is that on paper at least, Saudi Arabia has a more difficult game as it hosts Japan.
The Samurai Blue may have qualified already but will take a strong squad to Jeddah, though it does not include Shinji Kagawa.
It may well be that some of the competitive edge may be missing from Japan's game but players are already playing for FIFA World Cup places.
The standards that the four-time Asian champion has set over the years mean that the Green Falcons will have their work cut out. If the Saudis do win, it is likely to be a narrow and hard-fought victory.
Saudi Arabia is still kicking itself after letting a one-goal lead slip in the United Arab Emirates last week to lose 2-1.
Even a point would have made things easier.
Now, Bert Van Marwijk's men know that a win will only be enough if they don't allow Australia to make up the goal difference advantage.
WHAT IF...?
The first job for Australia is to defeat Thailand. Given Australia's immense home form, you'd think that's a genuine scenario.
If Saudi Arabia fails to defeat Japan in the early hours of the following morning in Oz, that will be enough for Ange Postecoglou and the celebrations can begin.
Yet if both teams win then goal difference comes into play. Australia's winning margin against Thailand will have to be three goals greater than Saudi Arabia's against Japan (see table).
If it's still equal, head to head will come into play, with Australia unbeaten against the Saudis (a win in Adelaide and a draw in Jeddah).
If Australia can get an early goal or two, it would not only put pressure on Thailand, it would do the same for Saudi Arabia, who'll be keeping a beady eye on proceedings from the King Abdullah Stadium.
Whatever happens, it is going to be quite a night. And morning.
There really is nothing like crunch World Cup qualifiers, is there.
