Defending ASB Classic champion Lauren Davis has been dumped out of this year's event, humiliated 6-1 6-2 by the unheralded Sachia Vickery.
Having muscled her way through the qualifying rounds, the 22-year-old Vickery made easy work of her American compatriot, winning in just over an hour.
Davis, who made a name for himself in Auckland last year with her tenacious style and grit, was barely going through the motions by the match's end.
She managed to win just 41 per cent of service points - including just 19 per cent of her second-serve points - and was visibly frustrated with herself.
The 24-year-old lashed out in irritation on multiple occasions.
Vickery, meanwhile, was far from perfect but nailed more than 60 per cent of her first serves and capitalised ruthlessly on Davis's implosion.
The Florida-based world No.122 will face Veronica Cepede Royg next, following the Paraguayan ace's 6-3 6-3 demolition of Spaniard Lara Arruabarrena.
The victor is then likely to play Agnieszka Radwanska.
"Honestly, me coming through qualifiers, maybe I had a slight advantage because I'd already played a few matches and this is her first," Vickery said.
"Sometimes it's not such a bad thing, to go through qualifiers.
"I'm just taking it match by match - I've been playing well, I like the courts here and the atmosphere, so I'm just going to keep on playing and fighting."
Vickery defeated Pole Magdalena Frech, Swiss player Conny Perrin and Italian Deborah Chiesa on the way to this week's Classic main draw.
Davis, meanwhile, has won just 10 matches since the start of April.
Earlier in the day, seventh-seed German Mona Barthel was downed 6-2 6-2 by American Varvara Lepchenko, while Sofia Kenin beat Jana Fett 6-4 6-4.
Kenin and Lepchenko will face off in the second round.