The fourth-placed UAE kept alive their slim hopes of a first appearance at the World Cup since 1990 with a come-from-behind 2-1 win in Al Ain City on Tuesday.
Ange Postecoglou's Socceroos remain in third spot behind the Saudis, despite having the same number of points and goal difference.
A draw would still move them above Bert van Marwijk's side and into the automatic qualification spots.
A defeat would require victory over Thailand in Melbourne next Tuesday and a Saudi Arabia loss to Japan in Jeddah to secure a top-two finish.
Al Abed put the Saudis in front from the penalty spot in the 20th minute, but Ali Mabkhout levelled the score less than a minute later with a fine effort on the turn.
Saudi Arabia's Osama Hawsawi hit the crossbar shortly after half-time, only for former Asian player of the year Ahmed Khalil to score a spectacular long-range winner on the hour mark.
Mahmoud Khamis of the UAE was sent off for a second bookable offence in the dying seconds of the game.
The team that finishes third will be left facing a tough road to Russia starting with a play off against the third-placed team in Group A, which is likely to be either South Korea or Uzbekistan.
They would then need to see off the fourth placed nation in the South and Central American group, which could be Costa Rica, the US, Panama or Honduras.
The UAE result leaves open the possibility that the Socceroos could finish fourth and be eliminated from World Cup qualification entirely. They would need to lose both of their remaining matches whilst UAE win and make up the goal difference between the two sides.
