Australian football fans were Sunday treated to an extraordinary A-League match as the Western Sydney Wanderers beat the Brisbane Roar 5-4 in extra time to advance to the grand final next week.

The Wanderers were 3-0 down in 23 minutes, but fought back to win the semi-final in an epic showdown that equalled the highest number of goals scored in an A-League game.

The Roar raced to what seemed to be an unassailable lead, kicking off the goal fest after Dimitri Petratos netted a penalty in the 16th minute when the ball was handed in the box.

Andreu Guerao Mayoral added to the Wanderers' misery when he scored an own goal in the 20th minute before Jamie Maclaren made it three in the 23rd minute.

But the Wanderers -- the only A-League side to have lifted an AFC Champions League trophy -- fought back in a sensational comeback as Dutchman Romeo Castelen scored in the 26th, 53rd and 59th minutes to level the score 3-3.

Brendon Santalab added his name to Western Sydney's scoresheet in the 39th minute while Dario Vidosic scored the decisive goal when he hit the back of the net in the 12th minute of extra time.

The Wanderers face Adelaide United, who beat Melbourne City 4-1 on Friday night, in the grand final to be held at the Adelaide Oval on May 1.