Liverpool set up a Europa League quarter-final clash against Borussia Dortmund after Thursday night’s 1-1 draw with Manchester United at Old Trafford.
Philippe Coutinho, Roberto Firmino and Daniel Sturridge scored for Liverpool across the two-legged tie in their first meeting in European competition.
Klopp was appointed as Brendan Rodgers’s successor in October after the 18-time English champions made a disappointing start to the season.
Former Liverpool midfielder Hamann talked up Klopp’s impact and ability to improve the performances of his players.
“There are a few players who have been brought into the club with a big reputation and they haven’t lived up to them over the past 12 or 18 months,” Hamann told ITV Sport.
“Some of the players are starting to believe now. The change of manager gave them a new lease of life. There are some players that you can build a team around them.”
Liverpool are in eighth place in the Premier League table and seven points behind fourth-placed Manchester City, who occupy the final Champions League qualifying spot.
The Reds lost their first final under former Dortmund manager Klopp after a penalty shootout defeat by City in the League Cup showpiece at Wembley.
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