The Jets will storm into a drought-ending finals series on a high after clinching their first F3 derby win of the season in front of 20,930 fans at McDonald Jones Stadium on Saturday.
Star striker Lachlan Rose's (calf) absence mattered little as local product Will Dobson opened the scoring in the 21st minute, before Clayton Taylor added another four minutes later.
Eli Adams made it three before halftime with his 44th-minute header and Kota Mizunama landed the final blow by capping a brilliant chain in the 86th.
The Anzac Day victory means the Jets (48 points) finish with 15 wins in a fairytale transformation under coach Mark Milligan.
Bolstered by steady ownership under Maverick Sports Partners, Newcastle will play finals for the first time since finishing runners-up in the 2018 premiership and championship.
Milligan, an 80-cap Socceroo who played at the 2014 and 2018 World Cups, said winning the premiership ranked "very high up" in his career.
"The number one goal for us was to get this club back to what I knew it was many, many years ago," Milligan said.
"To earn the right to have the local people of Newcastle come and support, enjoy, and love watching football again - from that point of view, I'm so proud of what these players have achieved so far.
"The mentality that they've had from day one in terms of their work ethic and that ruthlessness and being brave, it starts again on Monday."
Newcastle earn a week off in their hunt for an unprecedented domestic treble after winning the Australia Cup in October.
The Jets have won just one championship to their name, beating the Mariners 1-0 in the 2007/08 grand final.
Central Coast have now missed the past two finals series after finishing ninth (32 points) under coach Warren Moon.
They at least deny their local rivals the iconic F3 derby trophy, retaining bragging rights after an opening-round 3-2 win before a goalless draw in round 19.
The Mariners had helped the Jets clinch the premiers plate last round after pulling off a 1-0 upset to deny Auckland FC back-to-back titles.
Central Coast are now on the lookout for a new coach and owners, with Moon departing for family reasons after replacing treble-winning boss Mark Jackson on the eve of the season.
Unlike Newcastle, the cash-strapped Mariners have been propped up by the Australian Professional Leagues since January.
English second-tier side Queens Park Rangers have reportedly emerged as the frontrunner to purchase the club.
Moon could only praise the efforts of his players and staff.
"We had to suffer and we had to find a way to be competitive," he said.
"We've given it a good shake. There's a lot to be proud of with this group and the club and I'm just so proud to have coached these boys.
"They've taken everything that's come before them, with the ownership things and the club issues."
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