Ian Foster said New Zealand are "hurting greatly" and Sam Cane admitted they "weren't good enough" in a shock historic defeat to Argentina.
The All Blacks were expected to respond to a loss against Australia last weekend with a Tri Nations victory in their third match of the tournament at Bankwest Stadium on Saturday.
Argentina had other ideas, beating New Zealand for the first time at the 30th attempt with a 25-15 triumph in Sydney.
Nicolas Sanchez scored all of the Pumas' points in a stunning victory that was even more impressive given it was their first match since October 2019 at the Rugby World Cup.
New Zealand have now lost two out of three Tri Nations matches and head coach Foster said they could have no complaints after losing back-to-back Tests for the first time since August 2011
"It was the second week in a row we haven't had good composure when things didn't go our way," Foster said.
"We're hurting greatly but they should be very proud of their team. It was a historic win for them."
Cane doffed his cap to Argentina, but felt New Zealand left themselves down.
"The lesson is in Test match rugby you've got to turn up with the right intent, the right attitude every single weekend, or you get it handed to you," said the All Blacks captain.
"They were good, and we weren't good enough. Their defence was outstanding."
Cane scored a second-half try and Caleb Clarke touched down late on, but Argentina had a famous victory in the bag by then.