Manchester City boast the best defensive record in the Premier League, but Sir Alex Ferguson is well aware of his own side's shortcomings. "If we defend like we did at Reading [last Saturday, in a 4-3 win] we'll be in trouble," he said in the week. That performance was hardly an isolated horror show – 10 Premier League sides have conceded fewer goals this season, and United's defence has looked vulnerable to various methods of attack, from pace and movement in the home defeat to Tottenham, to an aerial bombardment from corners at Reading. Clearly, there are multiple problems at the back.
The purchase of Robin van Persie and Shinji Kagawa constituted an attacking shift in United's play – they have scored nine more goals than any other Premier League side this season. But forwards have often have deputised in midfield positions, and rarely has the defensive structure of United been so unclear under Ferguson, who traditionally orders his midfield to protect his back four.
Goalkeeper rotation has hardly helped – David de Gea deserves a starting place on a consistent basis – but maybe United miss Nemanja Vidic. Not necessarily for his defending in open play, where Rio Ferdinand, Jonny Evans and Chris Smalling are perfectly competent, but for his leadership skills.
The set-piece concessions at Reading, combined with United's incredible tendency to concede the opening goal, which has happened 15 times in 23 games this season, suggest a lack of focus and organisation. United face an uphill struggle to keep a clean sheet on Sunday, so will need their strikers to maintain their form.