The Red Devils finished one point adrift of the Stamford Bridge side last season after suffering home and away defeats to Carlo Ancelotti's men.
Despite the regular threat of Arsenal and the ambition of Manchester City, Ferguson feels it is the reigning champions who are their main rivals this term.
"The Premier League is such a difficult league, it's almost tribalism and you can't dismiss that impact when it comes to winning the Premier League," the Scot told CNN International.
"I always look at the team that wins the league the year before, you have to have a target to try to work on.
"It's up to the rest, including us, to do that and Chelsea are the champions. They've had a good start to the season and I look upon them as the main danger to us.
"The games that will matter will probably be the ones against each other. Last year we lost both of those games and therefore that decided the title."
Ferguson missed Wednesday night's 5-2 Carling Cup third-round triumph away to Scunthorpe as he was in Spain scouting forthcoming UEFA Champions League opponents Valencia.
The vastly-experienced coach has identified Real Madrid as a threat in Europe's Premier club competition this term as they are now under the guidance of former sparring partner Jose Mourinho.
He added: "You expect great improvement from Real Madrid under Jose Mourinho.
"Barcelona are still the most attractive team and they will be one of the main dangers with Inter Milan the most difficult to beat.
"They've all got their different qualities, but it's such an exciting tournament, you can't help but look forward to it. The Champions League is the most fantastic competition now."