Former Fiji netball coach Vilimaina Davu is back at her menacing best.

Davu helped her Northern Mystics team beat the NSW Swifts 58-33 in a Trans-Tasman netball preseason tournament in Queenstown.

Mystics new coach Te Aroha Keenan, who took over from Yvonne Willering who was sacked in the off-season, was impressed with Davu's performance and said give her a few more weeks and she will again be regarded as the best defender.

The result left the Mystics as the only unbeaten team in the tournament which also featured the Southern Steel, Central Pulse and the Australian Institute of Sport.