Hamann has been hugely impressed by both his ability and mental strength.
“Joe Allen has been outstanding since he signed,” Hamann told the Liverpool Echo.
“His awareness, his passing, the way he spots danger and helps out the full-backs, the wingers and the centre-backs, his work rate, his positioning - his all-round game has been fantastic.
“He has had a big influence on the matches. For a young kid to come here, go straight in and make such an impression takes a lot, especially in a team which hasn’t been winning games.
“There’s so much more pressure and expectation at Liverpool than he was used to before but he has adapted so quickly and made that step up.
“What I like about him is that he’s a real team player. He nicks balls, he wins it back and his passing is fantastic. He just plays his game and nothing fazes him.”