Manchester United boss Alex Ferguson believes that the Red Devils' title challenge will be “difficult” this season.

The 69-year-old, who led his team to a record 19th league title last season, is wary that he may face a battle to secure the Premier League trophy this year as he expects up to six teams to be in contention.

"I think you could say that five or six teams will be involved," Ferguson told Sky Sports News.

"It's always hard to win the league. It's a league that if you look at it, in the South you have the London teams like Arsenal, Tottenham and Chelsea and then you have ourselves, Manchester City and Liverpool in the North.

"It's a really, really difficult league to win."

United are back in action this weekend with an away fixture to Bolton in the evening kick-off on Saturday, September 10.