Cessnock sneak into the top five.
Kurri Kurri narrowly miss the semis after losing by a point.
Central win a fifth straight game to claim third spot, having been bottom of the ladder a little over a month ago.
And Maitland book a play-off position following 22 unanswered points in the final 20 minutes to come from 14 behind and beat Lakes, who end up with the wooden spoon.
That was the fall out from an enthralling last round of Newcastle Rugby League across the weekend.
With a multitude of scenarios possible depending on results, because just three competition points separated the middle four teams on the overall standings, the grandstand finish was set up when Cessnock beat Souths at Townson Oval on Saturday.
The Goannas jumped out of sixth after battling to an 18-14 victory against the defending premiers, who were well supported by the annual Sleapy's Day crowd.
At the same time the Pickers had a 34-26 success over Lakes at Maitland.
This, in turn, put pressure on both Central and Kurri at St John Oval to get something out of Sunday's clash.
A draw would have been enough for the Butcher Boys and Bulldogs, seeing Cessnock slip back out of the top five based on for and against.
Instead, Central captain Ethan Cook slotted a field goal in the dying minutes to seal a 13-12 win while Kurri had their season ended.
Finals-bound Cessnock rode an emotional 48-hour wave.
"That's what happens when you leave yourself relying on other results," Goannas coach Todd Edwards said.
"We made it hard for ourselves because of last week and the week before, but now we've snuck through we'll give it a go."
Cessnock now meet the Pickers at Maitland in Saturday's elimination semi-final with Edwards "proud" of the Goannas squad responding to a "scathing" review of last weekend's 57-0 loss to Western Suburbs.
Souths will host Central at Merewether in the qualifying semi-final on Sunday.
Butcher Boys coach Phil Williams said Central had got used to being in tight games during 2019: "The more often you're in those close ones, the more chance you have to win".
Kurri coach Ron Griffiths said it was disappointing the Bulldogs "didn't make the most of an opportunity".
In the remaining fixture and Wests defeated Macquarie 38-18 at Harker Oval with Rosellas second-rower Ryan Walker crossing for a hat-trick, which makes seven tries from his last two outings.
It was 24-18 at half-time with Macquarie scoring the first points. Wests, who have this weekend off as minor premiers, rested halfback Luke Walsh ahead of their finals campaign.
LADDER: Wests 28; Souths 18; Central 17; Maitland 16; Cessnock 15; Kurri 14; Macquarie, Lakes 10.