An outstanding kicking performance from winger Nico Scheepers saw Griquas stun the Sharks 32-30 in Durban on Friday.
The former Free State winger kicked eight from eight attempts at goal at Kings Park Stadium, including the match-winning conversion after the hooter to snatch victory away from the Sharks.
Scheeper's winning strike came after Griquas had pummelled away at the Sharks try line until they found a breakthrough, substitute Carel Greeff the man at the bottom of the pile.
It was a fitting end to a match that had been dominated by the side from Kimberley in the opening quarter.
Blindside flanker Marnus Schoeman crossed after an effective Griquas maul and two further penalties from Scheepers had the visitors leading 13-0 after only 15 minutes.
The Sharks were in desperate need of a response and they got it through two of their more experienced leaders.
Butch James added two penalties to bring the Sharks within range before Jacques Botes, who was a late replacement as captain for Keegan Daniel, clawed his way to the line after some sharp thinking from scrum-half Charl Macleod to level the scores at 13-13.
Botes was at it again before the half-time break, cancelling out a Scheepers penalty by reaching out for his second try after stepping inside the drifting defence - the Sharks ahead 20-16 at half-time.
With conditions worsening in Durban the rain dictated tactics for the majority of the second half.
Kicking became the best way forward and after Griquas crept in front thanks to two more Scheepers' penalties, the Sharks bit back.
An excellent positional kick from replacement Fred Zeilinga forced Gouws Prinsloo into an error, setting up a try for Lwazi Mvovo after good work from the veteran Odwa Ndungane playing at full-back.
The Sharks appeared to have the result sown up, before Greeff and Scheepers combined to send the crowd into deathly silence. A shock win to open the 2013 Currie Cup.
Tries: Botes 2, Mvovo
Cons: James 3
Pens: James 3
Tries: M Schoeman, Greeff
Cons: Scheepers 2
Pens: Scheepers 6
Sharks: 15 Odwa Ndungane, 14 Sizo Maseko, 13 Louis Ludik, 12 Tim Whitehead, 11 Lwazi Mvovo, 10 Butch James, 9 Charl McLeod, 8 Keegan Daniel (captain), 7 Jean Deysel, 6 Brynard Stander, 5 Marco Wentzel, 4 Edwin Hewitt, 3 Wiehahn Herbst, 2 Kyle Cooper, 1 Dale Chadwick.
Replacements: 16 Craig Burden, 17 Rayno Gerber, 18 Peet Marais, 19 Tera Mtembu, 20 Cobus Reinach, 21 Fred Zeilinga, 22 Jaco van Tonder
Griquas: 15 Gouws Prinsloo, 14 Nico Scheepers, 13 JP Nel, 12 Howard Mnisi, 11 PJ Vermeulen, 10 Francois Brummer, 9 Jacques Coetzee, 8 Burger Schoeman, 7 Jaco Negpen, 6 Marnus Schoeman, 5 Ligtoring Landman, 4 Hilton Lobberts, 3 Lourens Adriaanse, 2 Ryno Barnes (capt), 1 Steph Roberts.
Replacements: 16 Matthew Dobson, 17 Nick Schonert, 18 Jonathan Adendorff, 19 Carel Greeff, 20 Marnus Hugo, 21 Du Randt Gerber, 22 Rocco Jansen.
Referee: Jason Jaftha