Brisbane became the first side to win back-to-back A-League grand finals with their dramatic 2-1 victory over Perth Glory on Sunday and Postecoglou knows all too well his players are wanted men.

The Brisbane coach lost a number of key figures following the Roar's 2011 grand final triumph, including former captain Matt McKay, Kosta Barbarouses and Jean-Carlos Solorzano.

"It's a constant challenge (keeping the side together)," Postecoglou said.

"We work really hard to try and keep the core together and 90 percent of the squad is contracted for next year.

"But I had 90 percent of the squad contracted last year and the reality of it is we had to sell some pretty significant players.

"I'd like to think that the core of this group will be here next year and I think they will, and I think that's the key thing.

"The more stability you have in the playing ranks in this competition the better (placed) you are to repeat your success.

"With this success we've had I'm sure the players will be targeted, particularly from overseas and there may be a battle to keep every one of them here."

Besart Berisha, who joined Brisbane in the wake of Barbarouses' departure, was awarded a controversial penalty in stoppage time after Perth defender Liam Miller was ruled to have tripped him, although the Albanian did not appear to lose his balance due to the challenge.

However, the striker defended the decision on Monday, saying he was clearly impeded.

"They ask me a lot (about the contentious penalty), but I just saw some pictures this morning and you can see clearly the touch of the Perth defender," Berisha said.

"It was a touch, I lost my balance, it was a penalty.

"You must understand football is like this, it's not easy to lose and people always talk and say 'it wasn't a penalty' but nobody wants to lose the game and of course they talk about that.

"But it was a penalty, there was a touch, but this is the way it is in football.

"I understand Perth are very upset about this, they played a good season this year and I understand they are upset but they must also understand we deserved the win."