Ryane Clowe scored in the fourth round of the 1, at HP Pavilion.
Clowe started down the right side of the ice and faked a shot before cutting across to the left and lifting a wrister into the top-left corner past Jonathan Quick for the game winner.
Logan Couture scored San Jose's lone goal in regulation while Niemi made 28 saves in the Sharks' fourth straight win.
Richards notched a power play goal for the Kings, who had won three of their last four games entering Friday's action.
Quick stopped 34-of-35 shots.