Japan are primed to join South Korea at the London Olympics as they head into Wednesday's final round of qualifying pool games with a three-point cushion.
The 1968 bronze medallists need just a point to guarantee an automatic berth by finishing top of Group B, but a handy goal-difference means they could lose at home to Bahrain and still go through.
Syria are strong favourites to hang on to second spot, which would put them into this month's play-offs involving the three group runners-up, as they take on pointless Malaysia at home.
Third-placed Bahrain are level on nine points with Syria but they would need to beat Japan by a hatful of goals -- two weeks after their full national side beat Indonesia 10-0, prompting a FIFA probe -- to reach the play-offs.
South Korea went through with a game to spare after last month's win over Oman but Australia, who are still yet to score in five games, are playing only for pride when they take on Iraq in Gosford.
"It?s a bit different because we?ve had no preparation time at all. It?ll probably be a bit hit and miss -- the players will probably play on instinct and what they do naturally," said Australia coach Aurelio Vidmar.
"We?ll go through a few things of what we expect of them but I know there will be mistakes, which is only normal in a situation like this," he told the Football Federation Australia website.
"But on the flip-side they?re all very keen to represent their country and they?ll give 100 percent."
Uzbekistan have their fate in their hands as they entertain United Arab Emirates in Tashkent, needing to win by more than one goal to supplant the Group C leaders.
In Group A, Oman have a one-point advantage over third-placed Qatar as they look to preserve their play-off spot heading into their final fixture with Saudi Arabia. Qatar take on already-qualified South Korea.
Men's football is played as an under-23 tournament at the Olympics, although the rules allow for three over-age players.
The three group runners-up will play a round-robin tournament in Vietnam this month with the winner facing Senegal for a place at the Olympics.