The Blues are six points behind United after a third successive draw at Aston Villa on Tuesday night.
And Ferguson feels the champions' luck is deserting them at the wrong time as the Red Devils get back to full-strength with key players returning from injury.
"That's maybe Chelsea's luck changing," Ferguson told Inside United.
"They've had some incredible fortune in the last couple of years, scoring in the last minute against Wigan and Spurs last season, scoring in the first two minutes against us at the end of last season, things like that.
"For us, I don't think we've had any real luck in games. In terms of injuries we started off without the full squad - Gaby Heinze wasn't fit, we've had problems with Gary Neville, then Ji-sung Park and Ole got injuries.
"But we've coped really well because the squad has got stronger and more experienced so when players are out we're handling it much better."
Ferguson is also delighted with the good behaviour of the Red Devils this season.
"It has been terrific," he added. "Basically we're concentrating on the game all the time.
"We're not surrounding referees like other clubs do. There's a good core of natural discipline because we don't have any players who go over the top."
Let the mind games continue till May
