Barcelona striker Antoine Griezmann admits they weren't at their best for the 0-0 draw at Champions League opponents Borussia Dortmund.

Barca needed Marc-Andre ter Stegen to save a penalty to leave Germany with a point.

Griezmann said, "The penalty that Marc has stopped, other important stops. I think we have not knocked on the door ... These are things that need improvement. We must work and in the end a point is a point.

"A game away from home is always different, here or in any club. People press more and the local rival plays with more confidence. It costs us more.

"These are things to improve, let's see what we did wrong and improve."