A controversial late penalty saw Australia squander a lead against Syria, throwing fresh doubts over the Socceroos' chances of advancing past the play-off stages and their ability to cause any sort of damage in the World Cup itself.
The match finished 1-1, with Omar Al-Somah slamming home the spot kick with five minutes to play, cancelling out Robbie Kruse's first half opener.
The Socceroos must now either win, draw 0-0 or draw 1-1 and then win via extra time or penalties In Sydney on Tuesday to advance to a play-off against the fourth-placed North American team in November.
Australia had dominated the first hour of the contest, at a neutral venue in Malaysia, but whether it was the humidity, the conditioning or something else, the final 30 minutes felt like one-way traffic as the Syrians threw men forward to try and snatch an equaliser.
The Qasioun Eagles' effort was rewarded after winger Matt Leckie was judged to have pushed Al-Somah in the back while heading away a cross - Iranian referee Alireza Faghani's decision bewildering Australian players and fans alike.
"It's never a pen, but you come to expect that in this confederation," the Australian goal-scorer Robbie Kruse said after full time.
It could, and perhaps should, have been so much better for the Socceroos, who took the lead after 40 minutes with a superb dribble and pass from Leckie that allowed Kruse to tap home from close range - it was no more than Australia deserved after a dominant first half.
Tomi Juric should have made it 2-0 five minutes after the interval, only to send an attempted finish into the upright, before receiving the rebound and poking the ball goalwards into the same post for a second time.
Aaron Mooy ran the show in midfield, providing several sumptuous long balls to teammates that, on another day, could well have resulted in a far better scoreline for Ange Postecoglou's men.
But as the game went on, the Australian midfield tired, and the injection of Firas Al-Khatib nearly provided immediate dividends, with the veteran striker providing two dangerous crosses on his first two dribbles, the latter of which saw the ball come off Al-Somah and into the path of Mat Ryan, before hitting the underside of the crossbar and bouncing back to the Aussie keeper. That moment, perhaps, was a bit of karmic justice as replays showed Al-Khatib's dribble had taken the ball clearly beyond the line for what should have been a goal kick.
The Syrians pushed and pushed, and if not for key blocks on three occasions - from Leckie, Milos Degenek and Aziz Behich - the result could have been so much different for an Australian team that should have had the result beyond any doubt before Syria's comeback was allowed to happen.
It was nearly a dream start for the national team debut of Matt Jurman, starting in the heart of defence, who got his head to an early free kick but saw it miles wide of the target.
That chance seemed to spur Australia on, as the Socceroos dominated possession and chances - Juric had an open Kruse in the box but missed the target with a low pass, before a 20-yard strike from Mark Milligan forced a diving save from Ibrahim Alma.
Leckie and Kruse both wasted good chances shortly after that, but it was the Syrians who had the best chance to open the scoring, with Khribin blasting wide from close range. Then, with just five minutes to go in the half, the two German-based attackers combined to give Australia a priceless advantage in the tie.
The Socceroos could well have had a second before the break, with Leckie heading over, but it was not to be and instead, the road to Russia remains paved with potholes.