Sydney FC striker Bobo continued his fruitful second A-League spell, scoring the goal that ended the Sky Blues' derby drought and landing a hammer blow to Western Sydney's finals hopes in the process.
The Brazilian's 62nd-minute header from an exquisite dinked cross by Milos Ninkovic was his 10th goal of the season and secured the 1-0 win over the Wanderers at the SCG.
While that consolidated Sydney's hold on second spot, it left the Wanderers in eighth place and three points off sixth with just three games to play.
Coach Carl Robinson admitted they would probably have to win all three to make the finals, starting with a crunch home against seventh-placed Wellington Phoenix on Wednesday.
It was Sydney's first win in seven A-League matches against Wanderers, stretching back to December 2018, and they could have won by a larger margin but for some good saves from Daniel Margush.
After a tight first half of few chances, Sydney dominated the first 20 minutes of the second and Bobo's goal was a deserved reward for the home side.
"We moved the ball a lot better and we pinned them into their half a lot in that second half, which was the key in the end and a very good quality goal I thought," Sydney coach Steve Corica said. "It's very pleasing to have the (three) clean sheets and nine points in a week.
Both teams had the ball In the net from a first-half set piece, but neither counted. Bobo's slick 26th minute finish from a corner was scratched by referee Chris Beath after Rhyan Grant was adjudged to have pushed Mitchell Duke.
A couple of minutes before half-time Bruce Kamau rounded off a perfect corner variation with a precise shot into the net, only for the goal to be overturned by VAR for a block by Ziggy Gordon on Ninkovic.
The Sky Blues created more chances later in the half, with Anthony Caceres having a shot turned around the post by Western Sydney goalkeeper Margush.
The Wanderers custodian produced two more important saves in the first few minutes of the second half. He leapt to his left to push away a powerful Luke Brattan free kick and tipped a Bobo header from a corner over the bar.
The Brazilian was just off target with another header and Margush caught a sharp shot from Kosta Barbarouses as Sydney ramped up the pressure.
After Bobo's goal chances were few and far between with Troisi putting a free kick over the bar moments before being substituted.
Both sides had an attempt in the 78th minute, with Redmayne saving from substitute Bernie Ibini and Margush producing another good stop to deny Ninkovic, while Barbarouses was just off target with a long-range effort.
Robinson said it was a very difficult pitch to play on.
"I suppose it's like when you go into an attic in your house and you see that spongy stuff," he said. "There's an area of that field that wasn't great.
"I just don't think a Sydney derby, I don't believe any game should be played on a pitch like that."
Corica had no issues with the ground but said he would prefer to play any home finals at Netstrata Jubilee Stadium.