Hamann said: "You don't judge Michael on one game, you have to judge him on the goals he's scored for Liverpool throughout his career. He has been a prolific scorer for five seasons and no-one should ever forget what he has already done for the club. He always gets in the positions to get the goals but in football, nights like Wednesday can happen.
"Every striker in the world has nights where it just won't go in. Earlier in the season Michael had a bit of a bad patch and he bounced back by scoring a hat-trick at Manchester City. He's the type of player who can do the same again."