Borussia Dortmund forward Robert Lewandowski says his side must improve following their 2-1 defeat to Zenit in the Champions League round of 16 on Wednesday.
BVB progressed 5-4 on aggregate thanks to a 4-2 victory in St Petersburg in the first leg, despite losing on home soil on the night thanks to goals from Hulk and Salomon Rondon.
And the Poland international, who was booked during the clash and will now suffer a one-match suspension, has warned that last year's runners-up must be better in the next round.
"It was not the perfect match by us," he was quoted as saying by Uefa.com.
"We know we need to do a better job than this, but it is only important that we are through to the next round. Unfortunately I will miss the first leg of the quarter-final due to a suspension."
Team-mate Kevin Großkreutz agreed with his team-mate, but expressed his delight at progressing to the quarter-finals and is already eyeing a meeting with Barcelona.
"We were not compact enough in defence," Großkreutz told Sky.
"Zenit played well, they are a skilled team. But what matters is that we progressed to the next round.
"Barcelona would not be too bad. I've never played against them yet."