Young saved the crucial penalty to give Roar a 6-5 shootout win over Western Sydney Wanderers in Friday night's sudden death Elimination Final at Suncorp Stadium.

But that was not before Theo pulled off a string of stunning saves, including a spectacular double on six minutes, to keep the home side in the game.

Then, with the game finely balanced on a goal apiece in extra time, Theo was forced from the field with a suspected grade two medial ligament strain following a collison in the box.

Gripping shooutout sets up Victory-Roar semi

Gallery: Roar v Wanderers sudden death

It means the veteran goalkeeper will miss Brisbane's semi-final clash against Melbourne Victory and the rest of the club's AFC Champions League campaign.

The 36-year-old was a key figure in Roar's quest for a record fourth A-League Championship.

Coach John Aloisi said he never doubted Young's character at the big moment.

"“I was confident he was going to save at least one penalty because that’s the character he’s got - he believes he’s going to win football games for you and he did that tonight,” Aloisi said.