Friday night's win at Suncorp Stadium through a goal to Bozhidar Kraev took the Wanderers to 21 points and just one point outside the top six.
Brisbane lost their ninth home game in a row to sit last on five points in another underwhelming display.
Western Sydney took the lead in the eighth minute after a corner by Juan Mata that an unmarked Kraev headed home.
Henry Hore and the hapless Roar didn't take to their latest loss well. (Darren England/AAP PHOTOS)
Mata limped off minutes later with a hamstring injury and the former Manchester United and Chelsea representative is in doubt for next week's derby with Sydney FC.
The 1-0 advantage remained until halftime, with Roar goalkeeper Macklin Freke keeping his side in it with several key saves.
Brisbane were unable to make the most of their opportunities. Captain Jay O'Shea shot wide when he had a clear chance.
Striker Henry Hore had the best chance when his shot appeared set for goal before a classic block by defender Alex Bonetig.
The home side had the most shots on target, 5-4, but Wanderers goalkeeper Lawrence Thomas was supreme in keeping his side's second clean sheet of the season as the second half became a stalemate.
It was a sad night for the Roar on all fronts with 36-year-old stalwart Scott Neville retiring after his 300th ALM match. The veteran came off the bench in the last professional match of his career.
Nicolas Milanovic thought he'd doubled the Wanderers' lead but was denied by VAR. (Darren England/AAP PHOTOS)
Wanderers coach Alen Stajcic said his side fought hard for the win.
"The grind was there," he said.
"I probably thought we lost a bit of our fluency in attack to be fair. I thought combined with Macarthur and Sydney we were probably the best attacking teams up until the last week.
"We have traded in a bit of that attacking fluency for defensive resilience."
Stajcic said Mata's injury "might be one or two weeks".
Roar coach Ruben Zadkovich was frustrated after the loss. His side just never looked likely.
"It is frustrating for us because the players and the staff are working really hard but tonight we just weren't good enough," he said.
"I don't think we were polished enough on the ball and obviously conceded a soft goal early. You are chasing then and we didn't have enough moments of quality in our front five."
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