Brisbane's strong finish to the A-League season could come to nothing after Saturday's 3-0 defeat to Western Sydney dumped them out of the top six.
With just one match of their season remaining, the Roar were left to rue a terrible first half performance at ANZ Stadium.
With a superior goal difference, the Roar need at least a draw against eighth-placed Perth next week to be a chance of pipping the Wanderers for the last finals berth.
Brisbane impressed in winning six of their last 10 matches after a poor start to the season which had them seemingly destined for the bottom four.
But with a chance to lock up sixth, they were defensively sloppy in letting striker Oriol Riera put two goals past them in the opening 15 minutes at ANZ Stadium on Saturday.
"That's the disappointing thing, because we've actually put ourselves in a good position after a pretty hard start, hard three-quarters of the season, due to a lot of injuries," coach John Aloisi said.
"We've done well to get into this position to be fighting for finals and then we ended up performing like we did in the first half. "The players knew how important it was.
"We panicked a little bit in the first half because we conceded so early. Because we wanted to win the game, players started to chase the game instead of still sticking to our structures."
Aloisi admitted Ivan Franjic, Daniel Bowles, Thomas Kristensen and Fahid Ben Khalfallah played despite not being fully fit.
Defenders Franjic and Bowles picked up minor injuries in training last week, while veterans Kristensen and Ben Khalfallah have been nursing ongoing issues throughout the season.
They were risks the coach was willing to take.
"They've been starting and I don't like changing too many players," Aloisi said.
"We had to do that at the beginning of the season, changing players all the time. It's not good for cohesion.
"I decided they were going to be fit enough to play."
Aloisi remained confident the Roar will play finals, with the Wanderers to face fifth-placed Adelaide in the last match of the regular season.
"If we win that game [against Perth], we put pressure right back on them and Adelaide need a win because they want to climb the ladder as well," he said.