However a controversial penalty try awarded to the Stormers in the 66th minute greatly determined the game with referee Jaco Peyper ruling that Sharks scrumhalf Cobus Reinach played the ball from an off-side position and prevented a certain try.
That put the Stormers clear at 26-13 just minutes after Sharks flyhalf Pat Lambie reduced their gap to just 19-13 and everything to play for despite the more physical Stormers dominating the second period.
Using their set pieces and especially their dominant scrum as a base, replacement Kurt Coleman not only converted the easy attempt but also nailed a penalty in the 74th minute for a match-winning 29-13 lead.
It was the Stormers fourth straight win while the Sharks suffered their third loss in four starts despite the return of Boks like Frans Steyn, Willem Alberts and JP Pietersen.
Two yellow cards were awarded with Stormers No 9 Nic Groom ordered off in the 20th for collapsing a maul, while Frans Steyn was send off in the 72nd for repeated late tackle offenses, gesturing a sarcastic wave to the approving Newlands crowd.
Leading just 13-10 at halftime, Stormers flyhalf Demetri Catrakilis extended the lead to 16-10 four minutes after the break after the homeside earned another scrum penalty.
In the 49th Catrakilis also kicked his fourth penalty as the Stormers were building pressure on the scoreboard at 19-10 to the good.
The Stormers put massive pressure on the Sharks scrum in the opening half with the Capetonians securing no less than three tightheads in the first half.
Captains Duane Vermeulen and Bismarck du Plessis were also involved in a heated conversation after the latter killed the ball on the ground.
Sharks centre Frans Steyn was also in the limelight for three late physical charges on Demetri Catrakilis and Cheslin Kolbe (twice), but twice got the benefit of the doubt by referee Jaco Peyper.
Stormers loosehead Steven Kitshoff gave the Sharks Matt Stevens quite the workover before the Durbanites grew stronger in the latter stages of the first half.
The Sharks enjoyed the better start with flyhalf Pat Lambie kicking them to a 3-0 lead after three minutes.
But then a tactical kick by Stormers flyhalf Demetri Catrakilis in the 18th minute wrong-footed the Sharks for Stormers rightwing Johnny Kotze to dot down under the posts untouched for a 7-3 Stormers lead.
After relentless pressure Lambie scored the Sharks first try in the 24th minute despite a high charge from Stormers flank Nizaam Carr to surge the lead back at 10-7 before Catrakilis levelled matters 10-10 in the 32nd minute and added another in the 38th for a 13-10 halftime lead.