Dietmar Hamann believes Manchester United will have to produce a "near perfect" performance to beat Manchester City in Sunday's derby, live on Sky Sports Premier League.
Pep Guardiola's side have not lost a domestic game since April, a 2-1 defeat to Chelsea, and lead their city rivals by eight points at the top of the league.
But Hamann, who was impressed by United's 3-1 win over Arsenal last Saturday, thinks Jose Mourinho's players have the big-game credentials to pose City a threat.
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When asked how do you beat City, he said: "You have to defend well, you have to take your chances and you must not give them any easy opportunities.
"I think you have to cut out mistakes, if one team at the moment can beat them I would be looking at Manchester United because in these big games they are usually very stubborn and very hard to break down.
"They got a great result at Arsenal, where they had probably been outplayed for most of the game and came away with a result.
"You can't give (Kevin) De Bruyne any space, he is the heartbeat of everything good Manchester City is doing. Obviously Pogba is a big loss, but you need to play a near-perfect game, take your chances and they have a good goalkeeper so they should be OK."
United could go 11 points adrift of the visitors if they lose on Sunday and the former Manchester City man warned the hosts that they "can't afford" to lose the game if they want to stay in the title race.
"I think over the last few years City have gone into the game as favourites and it's the same this time around because they are going so strong in the league," Hamann said.
"It's probably a game United can't afford to lose because otherwise the gap might become too big with the way City is going at the moment.
"I think it's very hard to make up five or six points, let alone nine or 10."