The reigning Bundesliga champions also struggled to score at Anfield in the first leg.
“Of course, we knew it would be a tough game.
“But in both games I think we played too defensive. We didn’t try to push forward to create situations – in the first game and today.
“We didn’t risk much, we were playing at home it was our game but that’s why I think Liverpool beat us. We were playing too deep, we didn’t take risks, I don’t know why.
“We tried to push Liverpool but offensively sometimes it was two against four players and that’s why we didn’t do much.
“I have a lot of duels today, it was very difficult because I was alone.
“If you are alone against two or three good players it’s very difficult to play,” Lewandowski told Viasport.