Adam Le Fondre scored possibly the easiest goal of his career when a cross skimmed over the heads of everyone in the Perth box to bounce off his chest into the gaping goalmouth from just inches out.

But the goal just after the half hour mark was enough to separate first and second places โ€“ and left the Sky Blues full of confidence ahead of the finals.

Melbourne Victory likely need to beat Adelaide United over the weekend to keep their hopes of finishing second alive with another round still to go.

But Sydney feel like they are coming good at the perfect time to book a home semi final and then a Grand Final spot.

"We're hitting form at the right end of the year," said Brandon O'Neill at full-time. "And now we're looking forward to the finals.

"We've beaten the Premiers twice and looking forward to facing them again in the finals. I couldn't be prouder of the lads. It's just an honour to be part of these lads."

Coach Steve Corica added: โ€œWeโ€™ve beaten them twice now out of three. Theyโ€™ve had a very good season but our boys were sensational tonight.

โ€œItโ€™s important to get another win over them โ€“ itโ€™s a mental thing.

"Our boys know they can beat them.โ€

Skipper Alex Brosque missed his farewell home game of the regular season through a heel injury but was confident he'd be back playing in time for the finals.

But it didn't stop fans celebrating the career of their longstanding captain and veteran with tifos and a post-match party on the pitch.

For retiring Perth Glory veteran Brendon Santalab, there was little consolation from his night.

Despite playing the full 90, he was unable to find the back of the net but insisted the loss hadn't taken the shine off the Premiership glory.

"I thought it was a great performance," he said. "We did very well. We copped a sloppy goal bu the discipline throughout the game and the way we controlled the play was fantastic.

"The new boys got another chance to run out which is great and we'll go into the major semi fit and ready."