Now, they wait to see how the rest of the last round plays out over the weekend.

The result elevated the Jets to 33 points and onto level footing with Western Sydney and Melbourne Victory, who play on Saturday and Sunday respectively.

Newcastle are fifth, edging the Wanderers on goal difference and ahead of Victory by wins.

At the heart of the victory, the club's biggest since the competition's inception in 2008, was Robertson.

The diminutive 21-year-old was signed by the Jets on Thursday morning, before they flew to Adelaide for the biggest game of their season, as an injury replacement.

No.1 keeper Izzy Nino was sensationally red-carded in stoppage time of their crucial 3-2 win over Victory last Saturday for a scuffle with Emily Gielnik and consequently suspended for two games.

With No.2 shot-stopper Kiara Rochiax sidelined after finger surgery, it left the Jets with just 17-year-old rookie Lily-Rose Dunbar available.

But the addition of Robertson, who came through the Jets Academy and was signed from University of NSW in NPLW NSW, proved a masterstroke.

Before the Jets broke the deadlock in the 27^th minute and opened the floodgates, Robertson made several crucial saves.

Robertson was composed, calm and confident under pressure.

She tipped shots over the bar and around either posts at full stretch, came rushing off her line to deny Adelaide attacking raids with diving saves and plucked aerial threats out of thin air.

Home-grown captain Cassidy Davis, who has played just one semi-final in 11 seasons, marked her 150^th appearance for the club with a stunning left-footed strike from outside the 18-yard box to open the scoring in the 27^th minute.

The Jets' most-capped player then played a beautiful ball in behind Adelaide's backline to set up Lara Gooch for the second goal in the 42^nd minute.

Davis found Gooch in space on the right and the Young Matildas forward cut towards goal then scored at a tight angle between Reds shot-stopper Annalee Grove, who grew up in Newcastle, and defender Jenna Holtz.

Lauren Allan sent the Jets to the break with a comfortable 3-0 lead in first-half stoppage time after cutting off Grove's goal kick then scoring into the bottom left corner with assistance from Sarina Bolden.

The goals kept coming in the second half.

Gooch made it a match double from the top of the 18-yard box in the 47^th minute after an assist from Bolden.

Sixteen-year-old midfielder Emma Dundas notched her first A-League goal in the 58^th, also from the top of the area after Gooch crossed into the box.

Melina Ayres again proved lethal off the bench, scoring in the 62^nd and 70^th minutes, then centre-back Alex Huynh buried the ball into the bottom left corner of the net from the edge of the 18-yard box in the second minute of stoppage time after a corner.

It was the first time in the club's history that the Jets had won three games in a row.

Only twice have they made finals - in the competition's first instalment in 2008-09 and in 2017-18.

Robertson replaced Nino in one of two changes to the Jets' starting side. Gooch came in for Sophie Hoban.

Wanderers play Wellington across the ditch at 2pm on Saturday and Victory face Sydney at Leichhardt Oval at 4pm on Sunday with the Sky Blues needing to win to seal the premiership.