Unlike in several instances this season, a leaky defence could cost Sir Alex Ferguson's men Sunday's Manchester derby.
Manchester United at risk from sore back
Manchester United are like the champion boxer who gets knocked down and keeps getting up again. It should not happen, but it does.
United go a goal behind in almost every game and almost always surge back to win. I have never seen anything like it in football and cannot explain it. It is not intentional; it is very risky.
When Mike Tyson got rocked with a punch, he was good enough to come back and give his opponent a taste of his own medicine. And plenty more.
United can usually do the same, but the law of averages will always see United caught out. And with three league defeats so far this season, it has been shown United are incapable of recovering all the time.
Coming back against Queens Park Rangers or Reading, as United have done recently, is almost expected, but if United go behind to Manchester City in Sunday's Manchester derby it will be far, far tougher.
United did not manage a shot on goal in the last derby at the Etihad Stadium. They were not good enough and deserved nothing from the game.
If United defend like they did at Reading last Saturday and concede three quick goals, they could be looking at defeat of the 6-1 sort.
United have to improve in defence, though that is easier said than done. When I played in the Manchester derby for United, we were expected to win home and away. City were not our biggest game by a long way. When I played in the Manchester derby for City, we were expected to lose home and away. United was our biggest game by a long way.
United were dominant then, but some results were surprises. If football was so predictable it would quickly become very boring, but expectations have changed radically since I played. I have spoken to City fans who are really confident about tomorrow's match and United fans who are very nervous.
It is as if City, rather than United, have the three-point lead, yet the mood is understandable. The Blues saw their side win both matches last season on their way to wining the league, while the Reds saw their side lose both derbies on the way to losing the title.
This derby is highly intriguing. United have scored far more goals than any other team, yet they are conceding more than most. Sunderland, in 17th, have conceded fewer goals than have United.
City are the only unbeaten team in the league and they boast the best defence, just 11 conceded in 15 games, yet they are three points behind United.
The Reds signing Robin van Persie has made them stronger than last season, while City have not been as convincing.
I was sympathetic to City learning and making gradual progress in Europe, but finishing bottom in an admittedly tough Champions League group is a failure.
So City need to retain the title. They have Joe Hart to thank for being outstanding in goal, they have an impressive young Serbian defender Matija Nastasic, but some of their stars have not shone like last season.
Yaya Toure has not had the same influence on games. David Silva has had a couple of injuries. He was vital in going past players and setting up Carlos Tevez or Sergio Aguero, yet Aguero has scored just five league goals, half Van Persie's total.
I sense that in finally winning the league, one or two City players feel that they have cracked it. That is a dangerous state of mind, especially when facing opponents who are doubly determined to beat any champions.
A draw would be a fine result for United. The three-point lead would be retained and the next derby is at Old Trafford. Other title challengers have already fallen away so it would not be seen as two points dropped. A win, according to my old boss Sir Alex Ferguson, would be one of United's best results.
Going for a draw is not United's style, but I could not see Ferguson bringing on an attacker if the scores are level with five minutes to play. He would be happy with his lot.
Ferguson has packed the midfield in recent games away at City, playing five to combat City's strength in the middle. Sometimes it works, sometime it does not.
A sending off, like Jonny Evans or Vincent Kompany in recent derbies, can have a huge effect on proceedings.
The eyes of the world will be on the match which has become one of the biggest games in football. And one of the attractions is that the game has become far less predictable then when I was putting on my boots.
Andrew Cole's column is written with the assistance of the European football correspondent Andy Mitten.
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