The Japanese team outscored their hosts by three tries to two in what is a historic occasion for the Sunwolves.
It left the 2012-2013 champion Chiefs embarrassed as they remain winless after three rounds.
A year ago, the Chiefs thrashed the Sunwolves 61-10, as the Japanese side went through their first three seasons of Super Rugby with a woeful record and their future in the competition in doubt.
But they showed signs of progress when they went within a point of upsetting the Waratahs last weekend, and against the Chiefs they stepped up another gear.
In the first half the Sunwolves had 60 percent of the possession, but the error-prone Chiefs conceded nine turnovers – despite having very little ball to work with.
After the break the Chiefs turned on the charm a bit more, but continued to cough up the ball and gift the Sunwolves opportunities.
They led 23-3 at half-time and held on as the Chiefs tried to rally in the second half.
Sunwolves flyhalf Hayden Parker, who converted all three tries and added three penalties, described the victory as “awesome” and a confidence booster for the side.
“It was really nice to score some good tries in the first half. The second half was pretty ugly and it felt like the game went on forever but the boys hung in and I’m proud of the way we stuck it out to the end.”
Chiefs scrumhalf Brad Weber said his under-pressure side could not expect to win with the number of errors they committed.
“You’re not going to win the game if you keep coughing up the ball. I think we coughed it up about 10 or 11 times,” he said.
“But you have to take your hat off to the Sunwolves. Their speed of ball and the way they were able to break tackles was pretty special and we have to take a hard look at ourselves because it was pretty embarrassing.”
Flank Shuhei Matsuhashi and lock Uwe Helu scored tries as the Sunwolves dominated the first half.
But despite dominating possession and territory they could not sustain the pressure and weak defence saw van den Heever score a third try for the Sunwolves before Etene Nanai-Seturo added a late consolation second try for the Chiefs.
For the Chiefs:
Tries: Nankivell, Etene Nanai-Seturo
For the Sunwolves:
Tries: Matsuhashi, Helu, Van der Heever
Cons: Parker 3
Pens: Parker 3
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