The Sharks' Super Rugby playoff hopes suffered a blow when they were surprisingly beaten 27-16 by off-form Stormers at Newlands.
The victory was a first in five games for the Cape Town-based side, who were missing skipper Siya Kolisi through illness and had rookie Josh Stander in the flyhalf position on Saturday.
The Stormers outscored their opponents three tries to one in a tough, physical battle as lock Cobus Wiese, centre EW Viljoen and flying winger Raymond Rhule crossed.
Replacement wing Kobus Van Wyk managed the only try for the visitors.
The Sharks trail the eighth-placed Melbourne Rebels by three points on the overall table, needing to defeat the Jaguares in Durban in their final game next weekend to stand a chance of making the quarter-finals.
Argentina's Jaguares have been guaranteed at least a wildcard berth in the playoffs despite a 43-34 loss to the Bulls earlier on Saturday.
The Stormers, who have a bye in the final round, have completed their Super Rugby season.
