The German, who completed his £9.8m move from Bayer Leverkusen on Thursday, believes that the Reds are capable of becoming English champions next term.
"I want to be a Premier League champion next season," he told reporters. "Yes, I believe we can go one better. We will give it our best in order to finish on top of the table.
"We came second in last year's Premier League, the best league in the world, so we don't have to hide from anybody."