Carra says there is a lot of hard work ahead.
He said: "Liverpool get a lot of criticism.
"People say we live in the past - that we should be winning this and that.
"But the truth is Liverpool have not won the league for the past 20 years.
"Kenny did a fantastic job in his first spell but Liverpool was already steeped in success. In the two years before his appointment they had been to two European Cup finals.
"I hear people criticise Gerard Houllier and Rafael Benitez, saying they are failures because they didn't win the league. - yet I have to disagree with that.
"But if Kenny can get us back to where we were when he left in 1991, that in itself would be a brilliant achievement."