Argentina's Jaguares have rallied from 13-5 down at halftime to beat the Blues 20-13 for their first Super Rugby win over a New Zealand team.
The Jaguares won on Saturday in Auckland with a forward performance which wrecked the Blues' scrum and damaged their lineout, allowing them to dominate territory and possession in a rain-soaked match.
They also received twice as many penalties as the undisciplined Blues but took time to turn all those advantages into a historic win.
The Jaguares scored an early try through captain Agustin Creevy when the Blues lost back-rower Akira Ioane to the sin-bin for a professional foul.
The Blues also scored when Ioane was absent to make the score 5-5, then led with a try to fullback Matt Duffie.
The Jaguares gradually translated set-piece dominance into greater control, holding the ball through long phases to score a try through winger Emiliano Boffelli - his ninth of the season.
They took the lead in the 62nd minute with a try to Tomas Lezana.
They held out a Blues' attempted comeback to post their third-straight win in Australasia after earlier beating the Melbourne Rebels and Brumbies.
"We are very happy," captain Joaquin Tuculet said.
"We worked very hard this week, we knew they had a tough team but we played well and won the game.
"I thought the forwards were amazing. The scrum was very good so I think the win was for them."
The Blues slumped to their seventh defeat in nine games.
"I think you have to look at the set-piece," Blues captain James Parsons said.
"Numbers one to five in these conditions have to step up and I thought we did well in the first 40 minutes but there were just too many errors in the second half."