The Welshman believes Sir Alex Ferguson's side will have to be at their best to get a result when they meet the pacesetters on Sunday afternoon at Stamford Bridge
And the Welshman also acknowledged that the Red Devils will have to be at their best when they travel to Stamford Bridge.
"Sometimes new players settle in straight away and that seems to be the case at Chelsea," Giggs said, as reported by Sky Sports News.
"They've got off to a great start this season, particularly in the league. We're going to have to play well if we're going to get a result.
"I don't know if they're the real deal but what they have got is that experience and the know-how of how to win a league.
"Obviously, having added to the squad like they have done, they're going to be right up there this season, no doubt."
Giggs went on to express his belief that Roberto Di Matteo's side will challenge for the title this season due to their "clever" attacking players and vast experience.
"Come the crunch, if they're there or thereabouts, they've got the experience like ourselves, like probably [Manchester] City now, to go all the way," he said.
"I expect them to be up there at the end of the season.
"I think it is a different sort of Chelsea team. In past years they've had Didier Drogba's power and the runs through from midfield of Frank Lampard.
"We've always thought of Chelsea as a big, strong, powerful team.
"They've still got that but they've added the likes of Oscar and Eden Hazard, and Juan Mata is into his second season and coming along nicely.
"They've got clever players who can play in the pockets and make it difficult for teams."