Stormers coach Robbie Fleck says poor decision-making and execution cost them dearly in Durban on Saturday.
The Cape franchise slumped to a 22-10 defeat, and have now lost five of their last six games.
Fleck's men had 54% of the possession, and made 1,031 running metres compared to the Sharks' 676, yet could only score one try.
'When we got linebreaks, [the Sharks] worked incredibly hard to get back to reset their line,' Fleck said at the post-match press conference. 'When we were close to their line, they defended well.
'I think we were pretty stupid. We took wrong options when we were threatening on their line. Again, it is something that we will work on.
'They defended well, but I also felt we really spread them and had them at sixes and sevens, but again it was poor decision-making, poor option-taking and execution that obviously let us down.'
While the Stormers still have a 14-point lead at the top of the Africa 1 conference, Fleck said they needed to win matches ahead of the playoffs.
'It was important that we won this game. We've just come off a tough tour and then a good win against the Blues. For us, it was important to win.
'It has got nothing to do about the log points or anything like that. We haven't qualified yet. There are still three games to go. We are not thinking about what the Bulls or the Cheetahs are doing, it is about us and improving every week and we didn't do that today.
'We are not proud of the performance, to be honest.'
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