Waitakere United set up a mouth-watering semifinal tie against Auckland City after beating Canterbury 3-1 at Fred Taylor Park yesterday.
The champions needed victory to keep alive their title defence and they now face a two-leg battle against their great rivals in a bid to qualify for a seventh straight final.
Waitakere, winners of the last four ASB Premierships, stuttered through the season and suffered five defeats, setting up yesterday's must-win match and virtual quarter-final against Canterbury.
The visitors needed a draw to seal fourth spot but their chances of earning that result faltered badly in a first half determined by the quality of Waitakere's set piece.
Richie Cardozo scored his ninth and 10th goals of the season - finishing second behind Emiliano Tade in the golden boot race - with both goals coming from an educated left-foot delivery.