Sir Alex Ferguson has delivered a game changer.

Before the Manchester United boss persuaded Robin van Persie to sign on at Old Trafford, the edge for the new Premier League season lay with champions Manchester City.

City possess the deeper squad, the best goalkeeper in Joe Hart, the more solid defence, an inspirational midfielder in Yaya Toure, and if Carlos Tevez means what he says about his problems being behind him, then they have a goal-scorer and goal-maker to rival the best.

They also have the knowledge and momentum of having been there and done it last season, seizing the title on the final weekend when United faltered.

But the brilliance of Ferguson is that Van Persie could change all that.

It is not just the fact that Van Persie scores goals, although 30 out of Arsenal’s 74 in the league last season is evidence enough of the Dutchman’s influence.

It is the fact that he appears to be such a perfect fit at Old Trafford.

His movement across the front line will give Ferguson options when partnering him with Wayne Rooney. One could play in the hole behind the other. They are both capable of the killer short pass as well as sticking the ball in the net.

Goalscorers and playmakers. A formidable combination.

The signing also gives United the sort of unpredictability which is priceless at the top level.

Ferguson is the master when it comes to signing make-a-difference players. It is why he persevered with signing Ruud van Nistelrooy in 2001, despite the Dutch striker having suffered a serious knee injury.

It is why he took a chance on Cristiano Ronaldo as an 18-year-old in 2003, buying him for STG12 million and selling him six years later for STG80 million.

Mark Hughes, Teddy Sheringham, Eric Cantona, Rooney. They all fall into the make-a-difference category.

Van Persie’s transfer has done something else also. Unless you are an Arsenal supporter, it has breathed vitality into the start of the new Premier League season which was in danger of being greeted with indifference in many quarters following the feats of Mo Farah and Jessica Ennis and Sir Chris Hoy and Bradley Wiggins and the rest of Great Britain’s Olympians.

Football deservedly has been compared unfavourably with Olympic sports this summer.

We remember too well the racism rows centring on Liverpool’s Luis Suarez and Chelsea’s John Terry last season and the antics of QPR’s Joey Barton, who was banned for 12 matches following his attack on three players in the last game of the season against Manchester City.

The contrast with the behaviour of Olympic athletes and how they dealt with defeat was stark.

England manager Roy Hodgson this week admitted footballers could learn much from the London 2012 Olympians.

“How well they performed in interviews, the humility they showed when they win, the grace they showed to people they had beaten. The way they showed and admitted their disappointment,” said Hodgson.

It would be naive to suggest the tribal nature of football could transform overnight but what an Olympic legacy it would be if in 2012-2013, for starters, players ceased to intimidate referees and refrained from diving and feigning injury and fans stopped hurling routine abuse.

Why should football have to put up with the sort of hate and vitriol which was gloriously absent from the Olympic Park?

On a football front it is difficult to see the Premier League title going anywhere but Manchester, with Arsenal having been weakened physically and psychologically by Van Persie’s departure and Chelsea in transition yet again and without the fire power this time of Didier Drogba.

How will Tottenham fare under Andre Villas-Boas? Can Newcastle repeat their surprise fifth place of last season and what about Liverpool? Anfield’s Brendan Rodgers, in particular, needs to come up with big answers.

And at the bottom? Chances are half the league could be involved in the scrap for survival. Undoubtedly, the world’s most exciting league is a two-tier league and QPR, Norwich, Wigan, Swansea, Reading, West Ham, Southampton, West Brom and Fulham face challenging months ahead.

Southampton, Reading and Norwich are my early candidates for the drop.

As for the title City were in pole position until Ferguson pulled off his transfer coup. Now it could hinge on Van Persie. If he remains fit then Ferguson is set to take possession of his 13th title.