Manchester United boss Sir Alex Ferguson is reluctant to pass judgement on Brendan Rodgers' work at Liverpool. The Reds are at Old Trafford tomorrow.

"It is difficult to say," said Ferguson. "When a young manager goes to Liverpool it is a challenge.

"Kenny Dalglish going back was a challenge for him.

"Anyone going to that club faces a challenge because they haven't won the League for 20-odd years.

"It is a long time for a club like Liverpool. So for anyone it is a challenge. And it is difficult to measure any Liverpool side at the moment with Liverpool sides of the past."