Wainui equalised 30 minutes into the second half, when a shot from Larisa Allan was deflected into the path of striker Katerina Ngarimu, who finished well.
Campion had a chance to regain the lead when Taylor Broughton ran on to a through ball played in between her and Wainui keeper Kristy Roa, in action again after a two-year layoff due to a back injury.
The two clashed heavily. Broughton went down, winded, and Roa emerged with the ball.
With five minutes to go, Rosa Evans scored a superb goal from the edge of the penalty area to put Wainui 2-1 up.
Both teams battled hard to the final whistle.
The Wainui player-of-the-match accolade went to skipper Lily Hall-Auckram, who covered well in defence.