Though not mathematically eliminated, Adelaide are now five points out of the A-League Men's top six and will not be able to make the playoffs if Western Sydney's fixture against Melbourne City this weekend produces a winner.
Battling to avoid a wooden spoon, Western had the visitors staring down the barrel of outright elimination when they raced to a 2-0 lead after 34 minutes through Matthew Grimaldi and James Donachie.
But Hiroshi Ibusuki dragged the Reds back into the game with goals on either side of halftime, before setting up Nestory Iranukda to complete the comeback in the 62nd minute.
However, there was to be one more twist when Connor O'Toole, only on the pitch because of a potentially serious injury to Khoder Kaddour, met a spilled Ben Garrucio cross at the back post and dinked home a late equaliser.
It spoiled what had been a dominant second half for the visitors, using the momentum of Ibusuki's penalty in first-half stoppage time to storm back to take the lead.
The Japanese striker restored parity in the 57th minute when he pounced on a Ben Warland header that bounced off the crossbar, before turning provider as he teed up Irankunda to drive into the box and place a shot into the bottom corner.
It was a sharp turnaround from an opening stanza where things weren't looking good for Carl Veart's side after a calamitous attempt to play out from the back by keeper James Delianov went straight to Grimaldi to send it back into an open net, before Donachie blasted home a corner.
O'Toole then popped up to ensure the hosts took something from the game.
