The France midfielder has made a sluggish start to life back at Old Trafford following his world-record transfer back to the club from Juventus in the summer.
Pogba scored his first Premier League goal for United in the 4-1 win over Leicester City last month but most Red Devils fans will agree that he is yet to hit top form for Jose Mourinho’s side.
The 23-year-old will have to justify his enormous price-tag with his performances for Manchester United in the coming seasons.
And former Arsenal star Merson says it is time that the midfielder stepped up ahead of Monday night’s trip to Anfield in the Premier League.
Writing in his column for The Daily Star, Merson said: “United will have to be solid, and Pogba will have to produce.
“These are the games they bought him for and he still has a lot to prove for the fee they paid.”
Manchester United head into the game three points behind Liverpool after seven matches of the new Premier League season.
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