Manchester United boss Sir Alex Ferguson conceded that a successful defence of the Premier League title is now 'very, very difficult' following Sunday's goalless draw with Blackburn Rovers.

United had the chance to retake top spot from Chelsea ahead of their trip to Ewood Park on Sunday.

However, a goalless draw on a weekend where the London club were engaged in FA Cup action left the Red Devils one point behind their title rivals having played one game more.

"It's going to be very, very difficult to win this league now," said Ferguson, whose side looked short of ideas in the final third without the injured Wayne Rooney.

"We'll have a lifeline if Chelsea blow it, but in their eyes they have an easy game against Bolton on Tuesday. They'll expect to win that and that would put them four points clear.

"Our play today in the last third wasn't good enough (and the result) isn't what we expected given the amount of possession we had.

"We had the chances in the game - I don't think Blackburn made any chances - but dominating possession isn't enough.

"You need to take your chances. We had enough opportunities to create chances in the last third. We should have done better."Subscribe to Football FanCast News Headlines by Email