Borussia Dortmund coach Thomas Tuchel was not impressed with his side's performance in Thursday's 1-0 Europa League win over Porto.
An own goal from Iker Casillas saw BVB reach the round of 16 after last week's 2-0 victory at home, but Tuchel wants to see more from his players.
"Even though we won, I am not satisfied with our performance," Tuchel said at a news conference.
"We lacked the precision to create many chances, our passing was too sloppy. We were not in great form and made too many mistakes. But the result is obviously perfect for us.
"If the goal was actually offside, that was fitting for our performance. We made things too complicated for ourselves.
"But in the end things went pretty smoothly for us this round and we did not expect that against a strong opponent like Porto. It was not all bad for us. We have made it to the round of 16 and I think we deserved it overall.
"But I can still be critical, even if we win."