Auckland will now travel to Otago for Saturday's elimination semi after the Volts secured third spot with the second-largest win in Ford Trophy history.
Hamish Rutherford stroked 126 from 90 balls and Neil Wagner took four wickets to lead their side to a 221-run victory over Wellington in Invercargill, leaving the hosts a solitary run short of the record they set in 2014.
Rutherford and Michael Bracewell (91) saw Otago crack their way to 362-8 after winning the toss, a total that proved no match for the last-placed Wellington, who wore torn apart by Wagner and Jacob Duffy (3-40) as they slumped to 141 all out.
Canterbury, already assured of top spot, failed to record the first unbeaten one-day season in 20 years, pipped in the final over by Northern Districts at Mt Maunganui.
Andrew Ellis' unbeaten 96 was the anchor in his side's total of 251-8, falling just short of his century after flicking one to the fence via his pads from the final ball of the innings.
While the Knights were always in control of the run rate, regular wickets gave Canterbury a chance. But BJ Watling and James Baker shared an unbroken 45-run stand for the eighth wicket to get their side across the line with two balls to spare.