"When you play the best teams in the competition you have to play at your best. I'm not sure we've done that.
"Both teams we've played against the last two weeks [Crusaders and Waratahs] we've struggled to win our own ball or clean ball.
"When we've done that, for example against the Chiefs the week before, we've scored some good set piece tries, as we have all year. I guess that comes down to pressure and the big moments in the big games."
Captain Nasi Manu said: "As forwards we weren't quite there at the set piece."
"They're a quality side and they played well, they really stretched us.
"Whether we might have been thinking too far ahead and weren't quite there, it's hard to measure, but the positives are we're still in the playoffs and we've got a big week ahead of us."
The Highlanders beat the Sharks in Durban 34-18 in April, which came as a surprise, and that result will be of comfort to Joseph, who not surprisingly is expecting a Crusaders-type approach from the South Africans.
"They'll kick it a bit. They'll maul us.
"Their game plan is pretty simple and they are a big pressure team."