First-five Marnitz Boshoff booted 22 points, including two drop-goals, to dampen the Super Rugby playoff chances of the Bulls as the Lions completed a surprise 32-21 win in Johannesburg.
The defeat means the Sharks will win the South African conference and leaves the Bulls to scrap for a wildcard place.
They currently sit ninth and trail the Hurricanes in sixth position by four points, with just two games remaining.
The Lions are 13th.