The Newcastle Jets' finals hopes are all but over after losing 3-1 to A-League Men derby rivals Central Coast, who came from behind at McDonald Jones Stadium on Saturday and remain in the hunt for a top-two finish.
For the Jets to makes the finals, they will need to comfortably defeat Sydney FC in the final round of the regular season and hope Wellington lose big to 11th-placed Macarthur, who have won only one of their past eight games.
The Jets' inferior goal difference will preclude them from the post-season if the two margins are close, and even if both fall their way, they must also hope eighth-placed Western United lose at least one of their final two games.
After they struggled to contain an early attacking onslaught from the Jets, the Mariners took the lead for the first time in the 58th minute when Samuel Silvera completed a brace.
"To do it in a derby like that was pretty good," Silvera told Paramount+.
"Against my old team, that's even better."
Down 2-1, Newcastle were thwarted in their pursuit of an equaliser when Brandon O'Neill received a second yellow card for his challenge on Silvera.
O'Neill was the Jets' hero in last week's defeat of the Bulls and his side appeared bereft of answers when he was forced from the pitch with half an hour remaining.
The 10-man Jets were officially out of the game after Marco Tulio tapped the easiest of goals away in the 69th minute.
"Fantastic win for us. If anything I'm disappointed there wasn't more goals scored at the end," Mariners coach Nick Montgomery told Paramount+.
"I thought they put up a fight for 20 minutes, and then after that it was one-way traffic."
The loss leaves Newcastle facing the likelihood of missing finals for the 14th time in 15 seasons.
The Mariners, meanwhile, retained the F3 Derby Trophy with their second defeat of their neighbours from three meetings this season.
They can also begin thinking about an automatic semi-final berth after drawing level with the second-placed Western Sydney Wanderers and third-placed Adelaide United on 41 competition points.
Central Coast will still rely on other results falling their way next weekend to lock up second place and their best finish to a regular season since their championship-winning 2012/13 campaign.
Newcastle had the better of the opening exchanges and drew first blood through Jaushua Sotirio.
Mariners goalkeeper Danny Vukovic deflected Sotirio's first strike away from close range but the Jets forward was not to be denied from the ensuing corner.
He snuck behind the pack to make good on Beka Mikeltadze's header in the ninth minute.
Central Coast were patient and equalised when Nectar Triantis belted the ball way upfield to Silvera on the left wing.
The former Jet flirted with the boundary and beat Thomas Aquilina in a one-on-one contest before sinking the ball into the far corner of the net.
His second goal came from close range, assisted by Tulio, who was inexplicably open in the box as he thrust what looked to be the final dagger into the Jets' season.
Englishman Carl Jenkinson received a straight red card for a hands-heavy challenge on Mariners striker Jason Cummings, adding insult to injury in the final minutes for the Jets.