The German goalkeeper told the Liverpool Echo: "It was a big chance for me to play so early - I have only been here for a short time - and if you had told me six weeks ago that I would make my debut against Manchester United, I would have said that was a dream.
"We now have a very important game in the UEFA Cup (against Metalist Kharkiv). We all want to qualify for the group stages and that is what we are working for.
"I played for Bayern Munich against Dynamo Kiev twice and it was always a hard match against them.
"We do not know a lot about them but they are obviously a good side, as they would not have qualified for the competition.
"We know it is going to be a tough game but we will be well prepared for them."