BRISBANE Roar coach Ange Postecoglou has unwittingly issued Adelaide United a challenge before Friday's clash in Brisbane.

Adelaide can become the A-League's party poopers by ending Roar's 31-game unbeaten run at Suncorp Stadium.

But with the Reds in all sorts of bother after three games, just weeks after being labelled title contenders without a ball being kicked, the feat appears to be out of reach.

Adelaide houses four ex-Roar players - title winning Milan Susak, Serginho van Dijk, Dario Vidosic and Spase Dilevski - but Postecoglou admitted there were no secrets to be told by any, particularly Susak.

Susak formed part of a Roar side who should be tagged The Invincibles, a nickname given to Arsenal during a 38-game unbeaten run in 2003-04.

Preston North End earned the original title in the 1880s after 22 games without a loss.

"Milan knows what we're all about ... putting in hard work," Postecoglou said.

"There are no secrets.

"The boys are playing the way we want them to play and we don't veer from that."

In the corresponding fixture last year Adelaide moved three points clear of the pack and was on its way to equalling a prior record - 13 games without failure - after a 1-1 draw with Roar at Suncorp.

Roar was bouncing back from its last defeat - a 3-0 loss to Melbourne Victory - when it was held before Postecoglou's side kick-started an amazing undefeated run.

Postecoglou has been accused of working his Brisbane squad extremely hard during at least one session a week with game day proving his fitness theory is correct.

Postecoglou said Roar's training tempo was much more intense than what the side sometimes experienced during 90 minutes of an official match.

And with players rarely picking up soft tissue injuries Postecoglou said it wasn't just good fortune.

"The relationship between the coaching staff and the conditioning staff has led to this," he said.

"We have purposely targeted training and the way we play the game as what we want to achieve week in, week out.

"We're always striving to be better than the last game and that's also in the minds of the players."

To label the side as being equal to the Barca would be ludicrous but one critic - Fox Sports' Adam Peacock - willed the hypothetical when he asked former Socceroo and AC Milan keeper Zeljko Kalac whether the Roar would be good enough to feature in Italy's Serie A.

Kalac scoffed at the suggestion while Postecoglou is a realist.

"One day the run will come to an end," he said.