But when the substitutions were made the German side took control of the game, scoring the first soon after the restart, a second on the hour and the final three in the last five minutes of the match.
"We know we need to correct things," said the Liverpool boss after the final whistle. "We made a lot of mistakes. We need to analyse why things have been going wrong and work hard to fix them.
"We can start next week with a new mentality and I am sure we will be much better on Wednesday. The only positive to take from the game in Mainz is that it was a pre-season match.
"It is clear we made a lot of mistakes and gifted them a lot of goals but it was not an official match. In the first half I thought we were the stronger side but after the break we made too many mistakes.
"In fact we have made mistakes in all three of our European friendlies and that's not normal for us. It's not normal to see Liverpool conceding so many goals and that's why I'm not too worried."
Liverpool team: Carson, Traore, Hyypia (Paletta 46), Carragher (Hobbs 81), Kromkamp (Peltier), Zenden (Riise 60), Gerrard (Garcia 72), Alonso (Diao 60), Pennant (Anderson 46), Crouch, Bellamy (Sissoko).
Subs not used: Dudek