The Reds have endured a stuttering start to life under the German coach, who was appointed as Brendan Rodgers’ successor back in October.
Liverpool have won games against the likes of Manchester City and Chelsea in impressive fashion, but have only emerged victorious from four of their last 10 Premier League matches.
The Merseyside outfit were forced to settle for a point as they scored a stoppage-time equaliser to rescue a draw in Wednesday night’s 3-3 thriller against Arsenal.
Former Arsenal man Merson feels that Klopp still has a lot to prove in the Premier League following his appointment at Anfield and believes that the Reds will have to win Sunday’s showdown with Manchester United.
Merson told the Daily Star: “I think Liverpool have got to win.
“They brought Klopp in with all this fanfare. People were talking about him being one of the best managers in the business. I haven’t seen anything yet.
“They haven’t improved since Rodgers at all. It’s damning, if they lose to United they can write off their chances of getting into the top four because they’re a long way behind.
“This used to be one of the biggest games around but it’s two fallen giants now if I’m honest. I mean, Leicester are a long way above them, never mind Arsenal and Manchester City.
“It’s not the biggest game in the football calendar any more, whatever United and Liverpool fans might say.
“But it should be fun to watch the way the two teams are playing, and it’s always full of drama.”
Liverpool head into Sunday’s game in ninth place in the Premier League table.
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