Auckland suffered a third straight 50-over loss while leaders Northern Districts also had their wings clipped in Hamilton yesterday.
With two rounds remaining, the Ford Trophy is fascinatingly poised.
ND and Canterbury are joint top and can feel good about their chances of being in the four-way playoffs.
But it's not so comfortable for Auckland, who remain on 12 points - having got just two points from their last four games - with Wellington now equal and Central Districts and Otago just two back.
Otago rattled up 332 for six in Invercargill, the highest one-day score on Queen's Park.