Jurgen Klopp has warned Liverpool fans not to expect instant miracles from him after inheriting a "huge challenge" from manager Brendan Rodgers.
The German was named as the Northern Irishman's replacement on Thursday in what is his first job since quitting Borussia Dortmund at the end of last season.
Klopp joined Dortmund in 2008 and won back-to-back Bundesliga titles in 2011 and 2012, before guiding them to a Champions League final a year later.
The Reds, whose last league crown came in 1990, sit 10th in the Premier League table, and the 48-year-old warns that change does not happen overnight.
"There is no doubt, this is a huge challenge, for me and my coaching team," he told German newspaper Bild.
"We knew that full well [when we accepted the job]. Liverpool have not had any success for a long time and they've changed the manager all the time.
"And now they have appointed a German who is no miracle worker. Progress is not possible without a bit of time."
His first game in charge is a trip to Tottenham Hotspur next Saturday.
