"It's always about being brave but especially with a high-quality team. If they get their confidence up you get smaller. You have to have your own moments. Every moment can impact confidence," Klopp told reporters on Wednesday.
"Forget about last week and we will face tomorrow night with a new attitude. We won't be flying a white flag. (Dortmund) can play better but so can we. We need to do better tomorrow night."
Klopp played down the importance of the away-goal advantage and said his side would not settle for a goalless draw, even though that result would send them into the semi-finals.
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"Only at 0-0 is it an advantage. If we win, we don't need it," the charismatic 48-year-old said.
Liverpool will be without captain Jordan Henderson and striker Christian Benteke but Klopp said he had no new injuries to contend with following their 4-1 Premier League win over Stoke City on Sunday.
(Reporting by Shravanth Vijayakumar in Bengaluru; editing by Clare Fallon)
