"We're on a different path now and that's where our focus is."
The Kiwis looked strong in the opening half with wings Dallin Watene-Zelezniak, Jordan Rapana and fullback Roger Tuivasa-Sheck all scoring tries, while they absorbed three periods of sustained pressure to restrict the visitors to a lone penalty goal.
Their defence held firm early in the second-half but it all went sour when Tonga stormed back with David Fusitu'a scoring twice along with Tui Lolohea and Will Hopoate to steal a 24-16 lead with 15 minutes remaining.
The Kiwis scored again with Tuivasa-Sheck getting his second four-pointer, but the pressure cooker environment saw them commit costly errors before Fusitu'a stole a third to seal the result.
"We let ourselves down in the discipline areas that were normally very good at and then that forced us to try and play some footy and caused us to make some errors," said captain Adam Blair.
"You've got to give them credit for the pressure they put on us and if you give them a bit of football and they're a hard team to stop."