Brisbane began the match well, enjoying the majority of possession and deservedly took a 1-0 lead at half-time courtesy of a Mitch Nicholls strike.

But the Wanderers came out with greater intent after the break, equalising through Mark Bridge before Youssouf Hersi scored the winning goal to complete a 2-1 victory.

Mulvey had recalled Massimo Murdocca to the starting lineup, and gave Luke Brattan a rare start, and the pair performed admirably in midfield in the opening stanza to shield the defence and provide plenty of passes to Brisbane's attacking players.

When Brattan was unable to continue beyond 55 minutes, Roar lost their structure and were overrun in midfield, the coach explained.

"We knew we weren't going to get a full game out of Luke Brattan. We hoped we might get an hour out of him. I thought in the first half he was excellent," Mulvey said.

"When we threw George Lambadaridis on, he took a little while to get used to it. He did very well when he came on but we just lost our shape for some reason.

"If you have a look at the goals, they had an overload on both goals - that's not good enough."

Mulvey will be unable to call on the experience of Besart Berisha and Shane Stefanutto for Roar's next game against Perth Glory, as both picked up their fifth yellow cards of the season on Sunday meaning they both earned an automatic one-match suspension.

However the manager preferred to dwell on the positives.

"There's many bigger clubs in the world than Brisbane Roar that have gone through rough trots like we're having from a results perspective," Mulvey said.

"But if you look at the performance from last week, performance to this week, it was much improved. There was much more quality and you had a bit of a glimpse of the future there with Corey Brown coming on and Julius Davies (Doe). And I thought that they added an injection of enthusiasm.

"We are hurting badly but we also have a desire to improve."

The tension that results from a difficult period for the club has an effect on players' composure on the pitch, explained Mulvey.

"We were the architects of our own downfall because we didn't defend well," he said. "When you're in this position, the nerve endings are pretty frayed.

"You can see with some of the passing in the first half, we got a little bit nervous with regards to playing the ball out from the back and we got caught in possession a couple of times.

"That's not what our normal game is like, but pressure does that to you. The pressure of the situation, where we're at.

"There was a palpable feeling in the stadium, the fans got a little bit nervous because we weren't bossing the game as we had done in the first half."

Mulvey had no excuses when it came to the Wanderers' second goal, in which Shinji Ono had returned from an offside position as Hersi collected the ball.

Ono did not play at the ball and therefore play was allowed to continue.

"From a technical perspective, I think that if you as a player see that somebody is in an offside position, you're expecting the flag," Mulvey said.

"And I think what we did is we took one or two half steps instead of really striding out to deal with the situation, whatever eventuated. The lad that got through, Hersi, in my opinion came from an onside position.

"The linesman was ready to flag it but I'm not making excuses. Maybe it was, maybe it wasn't. The thing that mustn't happen is that we stop defending it, and that's what we did.

"That's the criminal offence that we committed today, and that cost us the game."