The Red and Blue halves of Manchester might have united to turn the Premier League into a two horse race for the title.

But that is not all that unites the clubs as they prepare to face off on Sunday.

Manchester United and Manchester City have shown more weaknesses than strengths this season and the derby winner will be the one with the least fatal weakness.

United may have been scoring goals for fun with that forward line of Rooney, Van Persie, Chicharito Hernandez and Welbeck.

But they have been riding their luck this season despite major issues at the back with a tendency to concede the first goal. 

The Reds have already conceded 21 goals in just 15 games in the league with the back four getting little protection from the midfield whether that is Tom Cleverly, Michael Carrick or Paul Scholes.

Last weekend Alex Ferguson’s side were torn apart at the back by 19th placed Reading, conceding three goals which were masked somewhat by the four goals that they struck at the other end.

Slow starters

Over 30 per cent of the goals Manchester United have let in this season have come in the first 30 minutes.

Fortunately for United, City have been notoriously slow starters in the league this season with only eight per cent of their goals scored in the first half hour.

But the Reds will miss captain Nemanja Vidic’s leadership and decisiveness at the back.

They certainly missed him during last season’s 1 – 0 loss at the Etihad – a much more significant result than the 6 – 1 defeat at Old Trafford.

During that match, Ferguson uncharacteristically set his team up to be overly cautious but to remedy that he may loosen the leash on his players.

That could open up space in the hole for City’s David Silva if as expected he recovers in time from a hamstring problem.

The Spanish playmaker has provided an assist almost every other game with 40 per cent of those decisive passes coming from the zone in front of the opposition back four.

Silva has also clinched assists when he drifts out wide to the right which could mean Samir Nasri gets the nod to start on the left.

David Silva

If Silva moves towards the flanks to find space, the Frenchman can shift into his patrolling ground.

But if United go with the width of Ashley Young and Antonio Valencia, Roberto Mancini might prefer to start with Aleksander Kolarov wide on the left in front of Gael Clichy – provided both can recover from recent injury problems.

Kolarov on the left with either Mario Balotelli or Edin Dzeko in the front two could unsettle a United defence which has been susceptible to balls into the box.

Despite remaining unbeaten in the league so far this season, Mancini’s team has not looked convincing.

The goals have not flowed as freely as last term when they averaged 2.45 goals per game.

20 of City’s 28 goals this season have come when David Silva is on the pitch which underlines his importance when it comes to opening up the opposition.

But an overreliance on one player also makes them easier to defend against.

However if Silva can work his magic between the United lines then it is advantage City.

But United’s best bet is to throw caution to the wind and hope they can outscore their rivals in a high-scoring match.