Northern Mystics snatched a come-from-behind 50-49 win over NSW Swifts in a rough-and-tumble trans-Tasman netball encounter in Auckland on Sunday.

The win secures second place on the table for the Mystics, and means Waikato-Bay of Plenty Magic are assured of a fourth-place finish even if they lose to Queensland Firebirds on Monday.

The fifth-placed Swifts desperately needed a win to have any chance of challenging for a play-off spot and came out firing.

Shooters Carla Dziwoki and Sue Pratley were unerring, shooting at 100 per cent accuracy and receiving superb service from midcourters Kim Green and Vanessa Ware in driving to the circle edge.

The Mystics eased ahead 13-10 after 15 minutes, sparked by three finely timed intercepts from goal keeper Rachel Rasmussen and well-finished at the other end by shooters Cathrine Latu and Maria Tutaia.

Swifts coach Lisa Beehag benched Dziwoki at the first break, bringing on Amy Wild at goal attack and pushing Pratley back to goal shoot.

With circle defenders Sonia Mkoloma and Mo'onia Gerard upping the pressure, the Swifts started nailing the turnovers and finally hit the front 22-21 four minutes from halftime.

The Mystics rallied, but two quick goals right on the whistle gave the visitors a 27-25 lead at the break.

The Swifts worked hard to extend their lead in the third quarter, shutting down the Mystics' trademark quick ball into the circle and forcing the Aucklanders into too many high-risk passes as they tried to find Latu and Tutaia.

With her team trailing 35-39 at the three-quarter mark, Mystics coach Debbie Fuller made wholesale changes for the final stanza.

The most influential came in moving Temepara George to centre while former Silver Fern Grace Rasmussen took over at wing attack.

The lines into the Mystics shooters were simplified, and the Aucklanders' through-court pressure force vital turnovers which were converted to seal the hard-earned win.