English Premier League Champions, Manchester United are fully prepared to defend their title, according to Sir Alex Ferguson.
Sir Alex Ferguson has already shortlisted the Blues as their toughest rivals for domestic supremacy this season.
"Arsenal had a great run last season until they got injuries in March, while Liverpool have signed Robbie Keane and one or two others."
"But Chelsea are the most experienced and they might be our biggest threat."
Manchester United open their title defense on home turf against Newcastle United, this Sunday.
The Red Devils will be without Cristiano Ronaldo, Owen Hargreaves, Nani and Anderson for the game.
However, Sir Alex Ferguson hasn't denied United's interest in luring Berbatov to Old Trafford, as soon as possible.
"Nothing has changed, I can't say anything until a deal is done."