Popa frustrated by red card decision

Western Sydney Wanderers coach Tony Popovic described referee Peter O'Leary's 83rd-minute send-off of defender Matthew Spiranovic as 'beyond belief' following Saturday's heartbreaking 2-1 loss to Adelaide United at Coopers Stadium.

O'Leary issued Spiranovic with his second yellow card of the evening and instant dismissal following a physical altercation which saw Reds forward Pablo Sanchez go to ground holding his face.

The dramatic red carding reduced the Wanderers to 10 men and allowed United to attack with impunity, ultimately breaking the deadlock through Sergio Cirio in the 92nd minute to deny the visitors what would have been a hard-earned draw.

Popovic was dismayed with the call against Spiranovic, while also taking a sly dig at Sanchez for grabbing his face after a perceived clash of shoulders.

"How the referee can give that as a second yellow or just for one player and not the other player (when) he's five metres away and to deem that as some reckless challenge, is beyond belief for me," Popovic said.

"That changes the last 10 minutes.

"We were told it was retaliation by the referee; I asked him after the game.

"I couldn't get any information by the fourth official - he wouldn't tell me what the reason was.

"If two players are shoulder to shoulder and they're talking to each other, then send them both off, give them both a yellow card.

"If one can go down holding his face from a shoulder, we've got problems.

"Then you play (with) 10 men for the last 10 minutes and concede at the death which we've done the last two games."

Despite the sour conclusion, Western Sydney had some fine moments, particularly in an energetic first-half display.

The Wanderers attacked with system and purpose and were rewarded in the 19th minute when Labinot Haliti scored.

Further opportunities to extend the lead went begging for the underdogs before the Reds hit their straps after half-time.

"Away from home, against a good team, you wouldn't have thought we're a team that's down the bottom," Popovic said.

"We should have been out of sight before the (Adelaide's) first goal.

"The game should have been over by then.

"Anyone could have won that game after 1-1.

"But up until that point there was clearly one side that was the better team and we should have buried them and finished them off.

"The boys didn't deserve that (loss) in the end."

The Wanderers will have to get over the disappointment quickly and gear up for the crammed schedule ahead, starting with AFC Champions League action against Kashima Antlers in Japan on Wednesday, then back home to tackle Sydney FC in Saturday's derby at Pirtek Stadium.

"We go to a fantastic tournament now to defend our title. we'll go to Kashima and try to repeat that.

"We look forward to Japan, look forward to trying to do ourselves proud and trying to do the A-League proud again.

"We're embracing that challenge. We're proud to be in the ACL and we know that our catch-up (upcoming A-League) games are due to the success we've had."