The world champions Black Ferns have slumped to their first-ever test defeat against Canada, falling 22-19 to lose their Pacific Four series crown at Christchurch.
Winger Katelyn Vaha'akolo scored two first-half tries, as the home side led early, but they had no answer to their rivals after the break, as the North Americans used their set-piece to take control.
The result means the Canadians will finish the competition unbeaten, after earlier wins over USA and Australia, and leapfrong the NZ women to second in world rankings.
Cold, slippery conditions promised to make handling difficult and Canada knocked on the opening kickoff, but put first points on the board with a penalty to flanker Sophie de Goode.
New Zealand had the first try though, when they kicked to the corner and unleashed their backline from the lineout, with Vaha'akolo crossing in the corner, converted from the sideline by captain Ruahei Demant.
Vaha'akolo had her try double, when her forwards built phases and halfback Maia Joseph passed cleverly inside to put her winger through the defensive line.
Canada struck back from a close-range lineout, with winger Fancy Bermudez charging over from a ruck.
With halftime nearing, Maia Roos won an attacking lineout, but hooker Georgia Ponsonby was deemed held up over the line, despite replays to the contrary.
The Ferns were still up 14-10 at the break, but the North American forwards completely dominated the next half hour, scoring tries through Hunt and a second to Bermudez, with another disallowed for obstruction in the build-up.
New Zealand's predicament was not helped, when second-five Sylvia Brunt was yellow-carded, as penalties mounted.
With 10 minutes remaining and trailling 22-14, the NZ forwards piled up 36 phases from their own half to the tryline, searching for a way through. Canada lost halfback Olivia Apps for a dangerous tackle on Demant and, eventually, fullback Patricia Maliepo crossed for the try.
Demant's conversion fell under the crossbar and the Kiwis still needed a try to win. They would have to do it without prop Aldora Itunu, who saw yellow for collapsing a maul.
They repulsed another dangerous attack from the opposition forwards, but with seconds ticking down, Demant chose to kick, instead of keeping the ball in hand, and Canada were allowed to run down the clock on their breakthrough victory.
"We let them get on top of us," conceded shellshocked Ferns co-captain Kennedy Simon. "There's little things we could have fixed... congratulations to them.
"We just have to go away and reflect on ourselves, and make sure we turn up. It's not over yet."
New Zealand must still face winless Australia next Saturday and another shock loss would jeopardise their involvement in the WXV1 competition later this year.
Canada 22 (Bermudez 2, Hunt tries; De Goode penalty & 2 conversions) Black Ferns 19 (Vaha'akolo 2, Maliepo tries; Demant 2 conversions)
