A drop goal at the death from Stormers fullback Jaco Taute stunned the table-topping Sharks as he sealed an unexpected 21-19 victory in Super Rugby on Saturday.
Aside from a brief period in the first half, the Stormers trailed throughout the game until Taute's strike after the final hooter silenced the home crowd and left the Sharks with just a two-point lead over the second-placed Waratahs going into the June international break.
Sharks halfback Cobus Reinach scored the only try of a match in which kicking for territory featured much more prominently than creative running, as neither side showed a great deal of ambition.
That ultimately came back to haunt the Sharks, as the Stormers crept back from 19-12 down to steal the points.
''Every time they got into our half they got some points - our discipline let us down,'' Sharks captain Bismarck du Plessis said in a television interview.
''It was a real derby game where you can never see how it's going to go.''
As Francois Steyn and Kurt Coleman exchanged penalties over the course of the first 35 minutes, the only noteworthy incident came in the 10th minute when Stormers flank Nizaam Carr received a yellow card for a dangerous tackle.
However, Reinach livened things up two minutes before halftime when he surprised the Stormers defense with a quick pick and go to give the hosts a 16-9 lead at the break.
Coleman and Steyn added a penalty apiece at the start of the second half, and after Coleman was withdrawn with a black eye, Demetri Catrakilis added two more penalties for the Stormers - the second of them after Sharks flank Marcell Coetzee had seen yellow for repeated offsides by the home team.
That made it a one-point game as the Stormers pack caused trouble for their more experienced counterparts at set pieces, but despite those problems Steyn had two opportunities to give the Sharks some breathing room and shelled relatively straightforward penalties, one of which came off the crossbar.
That proved crucial when the Stormers got hold of the ball in the dying moments and Taute rounded off an otherwise disappointing individual performance by scoring the winning points.
''It's amazing to come out with our first away win this season, so we're very thankful for that,'' Stormers captain Duane Vermeulen said in a television interview.
Sharks 19 (Cobus Reinach try, Francois Steyn 4 penalties, 1 conversion) Stormers 21 (Kurt Coleman 4 penalties, Demetri Catrakilis 2 penalties, Jaco Taute dropped goal). HT: 16-9.
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