Australia's World Cup qualification group is extremely tight with the top three separated by just one point.
Each nation has two games left.
AFC has 4.5 spots in qualification for the next FIFA World Cup.
Only the top two in each group earn automatic entry to Russia 2018.
Third place in each group square off in a home-and-away showdown with the winner moving into a home-and-away intercontinental playoff against a CONCACAF nation.
KEY REMAINING FIXTURES
Japan v Australia in Saitama on August 31
UAE v Saudi Arabia in Al Ain City on August 31
Australia v Thailand at AAMI Park in Melbourne on September 5
Saudi Arabia v Japan in Jeddah on September 5
What if Australia and another nation finish on equal points at the end of the group stage?
If both teams have the same points then goal difference will be the deciding factor.
If the teams still can’t be separated, the side with the most goals scored in the group will book a place in Russia.
Still tied after that?
Then it’s the greatest number of points gained in games between the teams concerned.
In the case of Australia and Saudi Arabia, the Socceroos have four points and the Saudis one point from their two meetings.
THE UPSHOT: IT'S IN THEIR HANDS
The Caltex Socceroos know they will secure World Cup qualification with two wins.
A win and a draw might also be enough depending on other results.
However, both Japan and Saudi Arabia can also secure their spots with successive victories.
Regardless of what happens against Japan, Australia won't be definitely in or out when they return to Melbourne for their clash with Thailand.
But a win in the September 5 clash at AAMI Park may well see the Caltex Socceroos punch their ticket for Russia.
It could well be a night to remember.
This article was originally published at: http://www.socceroos.com.au/article/why-these-are-two-massive-games-for-australia/1pj4ybdg1m9471q4wsh6xpi89a.