Goalkeeper Karius broke his hand during pre-season and only made his debut in the 3-0 EFL Cup win over Derby County on Tuesday but his first performance for the Reds came with high praise from his colleague.
"One time he came out really nicely and was there in a one-v-one situation," Klavan said of Karius.
"I knew it already in Bundesliga that he was a really good keeper and was quick to come out.
"We are moving forward as a whole team and as a last line we have to be higher and it is nice when you have a keeper who is able to come out.
"I can only say what he was like in the Bundesliga and what I have seen in training.
"He is good with his feet, he is quick coming out and he is not afraid to come out for high balls, so in my eyes he is a really good keeper.
"I can also hear him talking to players."