The Red Devils head into their Premier League trip to face their local rivals after the disappointment of their Europa League exit at the hands of Liverpool on Thursday night.
United have come in for plenty of criticism in recent weeks for their below-par displays, and the Red Devils are currently sixth in the Premier League table.
However, Louis van Gaal’s men can move to within just one point of their bitter local rivals with victory at The Etihad on Sunday.
Former Arsenal star Merson, however, is tipping City to have too much for Van Gaal’s side and is expecting the Red Devils to slump to a 2-1 loss on Sunday.
Writing in his column for Sky Sports, Merson said: “Manchester City have to win this game.
“It’s all becoming very tight in the race for the top four and Manuel Pellegrini’s men are really struggling at the moment.
“The injuries to Vincent Kompany and Nicolas Otamendi are a big blow, however, I see home advantage being key in this game.
“Manchester United also have injury problems and a tough game against Liverpool won’t help their chances. I see City just edging this one 2-1.”
United finished fourth in Van Gaal’s first season in charge.
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