Sharks captain Keegan Daniel believes their defence will be severely tested by a strong Chiefs backline which includes centre Sonny Bill Williams.

Unbeaten in Durban this season, the Sharks are looking for a morale-boosting victory over the Chiefs who have lost only once in this campaign and started the round leading the Super Rugby standings.

"That whole backline is filled with X-factor players, not only Sonny Bill, but we've all seen what he's capable of with (former team) the Crusaders and when he's played for the All Blacks," Daniel said.

"He has an unbelievably good offload game which makes him exceptionally dangerous.

"He's a big guy who carries a lot of ball, so we will have to pay lot of attention to him.

"But in saying that, they have some unbelievable backs as well.

"Overall, it's going to have to be one of the biggest defensive efforts from us as a team."