Three teams remain as the season heads into its final fortnight but it is one-time premiership favourites Blacktown Spartans who have bowed out.
It was Sydney Olympic who did the job, winning 3-0, while in the other match Blacktown City qualified for the grand final by beating Bonnyrigg White Eagles.
Bonnyrigg White Eagles 0-1 Blacktown City, at Lambert Park
Bonnyrigg White Eagles, the premiers, blew a chance to go straight to the grand final by going down to Blacktown City who have earned a week off before the showpiece event.
It was a late penalty scored by Kearyn Baccus that separated the two sides in a cagey encounter that really opened up towards the back end of the second half.
The first half got bogged down as both sides looked to probe and create openings without leaving themselves too vulnerable to the counter attack.
With Matthew Nash missing through injury, youngster Tristan Prendergast deputised in goal again and distinguished himself early with a great one-on-one save to deny Mitchell Mallia.
It was the only genuine goal mouth action of the first half. Blacktown City's goalkeeper Nenad Vekic had his time to shine, making a superb save to stop Aaron Peterson's header from flying in to the top corner.
The game really opened up in the final ten minutes and Bonnyrigg had to try and hold on. Travis Major missed a great chance before Ben Spruce cleared off the line from a Matt Lewis header.
In the final moments a deliberate handball from Chris Tadrosse saw a penalty awarded to Blacktown City.
Baccus made no mistake, tucking it into the bottom corner to send Blacktown City to the grand final and condemn Bonnyrigg White Eagles to an elimination semi-final against Sydney Olympic next weekend.
Blacktown Spartans 0-3 Sydney Olympic, at Lambert Park
Where did it all go wrong for Blacktown Spartans?
They conceded 13 goals in their last three games and not once did they find the back of the net. It wasn't championship form and their season unravelled at an alarming rate.
Spartans were good for the first 45 minutes here but after that Olympic played them off the park and only the heroics of their keeper Carlos Saliadarre kept them in the contest.
His opposite number Paul Henderson was excellent in the first half, making a couple of excellent stops to keep his side level as Spartans looked to blow away Olympic with an early salvo.
But the second half onslaught saw Olympic deservedly go through.
Saliadarre denied Harris Gaitatzis early in the second half and then shortly after made a wonder-save to keep out an effort from Dimitri Hatzimouratis.
But in the 57th minute there was no more waiting as Hatzimouratis delightfully chipped Saliadarre to open the scoring. It was just reward for Olympic's second half dominance.
A number of athletic stops Saliadarre kept Spartans in with a shot but then two late goals for Olympic put the game to bed.
With three minutes to go, a loose ball fell to Go Shirai and the diminutive midfielder thrashed it home to double their lead and make the game safe.
With only seconds left, Olympic's Will Angel crossed to Harris Gaitatzis who added the third and the icing on the cake.