Newcastle finished the three-day, 18-game championship with a perfect record but they needed to win their final match against Manly Warringah, whose only blemish was a draw with Randwick, to take the crown.

Manly, the defending champions, trailed by two goals at half-time of the 24-minute match but Newcastle were soon three goals behind.

Newcastle's defence rallied and the 2017 champions levelled with three minutes remaining before powering to a 21-15 victory.

"Georgia McVey was outstanding at goal-keeper," Newcastle coach Traci Baber said.

"She made some beautiful, aerial intercepts to help bring us back to even and that spurred the rest of the team on and they found their mojo. But the whole team defensively was brilliant."

Newcastle, who finished with an impressive 565 goals for and 264 against, overcame the loss of centre Narelle Eather to a knee injury early on Monday, while Kim Williams played through a foot problem that will require surgery.

"I would say this was the hardest opens comp there's been for quite a few years as well," Baber said.

"A lot of the areas that played Metro League had teams in again, whereas a lot of the Sydney teams had been absent in recent years."

The final-day surge came after a two-goal win over Randwick late on Sunday. Newcastle defeated Randwick by one goal to clinch the 2017 title.

The Newcastle squad was: Tiffany Gilmour, Narelle Eather, Keeley Mullins, Sabina Gomboso, Abbie Gray, Karlie Robards, Kim and Angela Williams, Katelyn Stansfield, Georgia and Ellie McVey, Vo Smith.