Peter Betham scored two tries for the Waratahs while Israel Folau and Will Skelton crossed once each as NSW collected a much-needed bonus point to climb to sixth place in the standings after losing at home to the Stormers last week.
The Hurricanes also scored four tries and picked up a second bonus point for losing by less than seven to remain perched at the top of the table just over halfway through the season.
“Not a lot of people would have given us a chance coming over here (against) the ladder leaders,” NSW captain Dave Dennis said.
“It wasn't perfect but it's a win. Although they scored a lot of points, we still worked hard for each other so that's really positive.”
The Hurricanes botched a certain in the third minute when flanker Ardie Savea dropped the ball over the line after he had broken through the defence.
Betham opened the scoring with his first touchdown in the 14th minute but the New Zealanders replied with three tries from Conrad Smith, Beauden Barrett and Brad Shields to lead 19-12.
Betham scored his second five-pointer after the first half siren sounded to send the teams to the break level at 19-19 then the Australians regained the lead when the dangerous Folau crashed over in the 52nd minute.
Wellington scrum-half TJ Perenara scored a soft try 10 minutes from the end to cut the margin to five points but the Waratahs' defence held firm in a tense finish.
Original source: Waratahs upset Hurricanes in thriller