Difficult wet conditions led to a messy first half, with two Sias Ebersohn penalties for the Force providing the only points.
But tries from SP Marais and Lwazi Mvovo turned the game in the Sharks' favour as they improved after the break.
Frans Steyn and Ebersohn traded early penalty misses before the former was also off target with a drop-goal attempt.
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Force number eight Ben McCalman was controversially denied a try by television match official Marius Jonker, a decision surrounded by confusion in the stadium, and the Western Australian side instead had to settle for an Ebersohn penalty.
The first half was perhaps best summed up when a clearance kick from Ebersohn flattened team-mate Nathan Charles, forcing him off for concussion tests.
The hooker was passed fit and re-emerged to see Ebersohn slot his second penalty and the Force led 6-0 at the break - but not before Sharks pair Jannie du Plessis and Jean Deysel also appeared to knock each other out while trying, and failing, to tackle Kane Koteka.
The home side raised the tone two minutes into the second period when a break from Odwa Ndungane set up the chance from which Marais dashed over for the first try - Steyn once more inaccurate with the conversion attempt.
The Force lost captain Sam Wykes to concussion before the Sharks took the lead from a penalty, Fred Zeilinga taking over kicking duties to improved effect.
Ebersohn missed another shot at goal and was punished when Marais set Mvovo away down the wing for the second try, converted by Zeilinga.
Another Force try was chalked off after consultation with the TMO, McCalman guilty of obstruction before Steve Mafi touched down.
They also came up short when, after a spell of pressure, Kyle Godwin fumbled as he reached for the line.
But a missed penalty by Zeilinga at least allowed them to claim a losing bonus point with Luke Burton's successful kick after the hooter.
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