The 70-year-old believes his side, along with Chelsea and Manchester City, have stolen a march on the chasing pack and the eventual league champions will be one of those three.
Despite less than a quarter of the season having been played, Sir Alex views the Premier League as a three-horse race.
"I think Chelsea, City and ourselves are creating that little gap from the rest," he told The Mirror.
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"It's difficult to be dead certain, but I would be surprised if one of us three didn't win it."
United travel to Stamford Bridge to face early pace-setters Chelsea on Sunday, a game that Sir Alex thinks could have major implications for the title race.
"Our game on Sunday will be important to us, there's no doubt about that," he said.
"There are lot of big games still to come, of course, but I think it will be close.
"There are a lot of ways a league can be decided. The way we lost it last season is one way - on goal difference. That was unusual for us.
"But the way the league is now, any one of the three could win it, there's no doubt about that.
"All of us have strong squads, particularly Chelsea and ourselves, in terms of recent history.
"That will always guarantee we will be able to handle the number of games you have to play."