The Red Devils travel to play West Bromwich Albion in their curtain raiser in the league, but three of their next four games see Tottenham Hotspur, Arsenal and eventually Chelsea visiting Old Trafford.
The Scot, though, has hailed the younger players at the club for the enthusiasm shown during training, resulting in a fit squad ahead of the beginning of the campaign.
"I'm very pleased with the way pre-season has gone," the 69-year-old said, according to The Observer.
"The great benefit of bringing in a few new young players is that they bring their enthusiasm and hunger into training. The training sessions have been fantastic and I always say that what you see in training comes through in the way you play in games.
"You could see that quite clearly at Wembley last week. I know it was only the Community Shield but Manchester City weren't as fit as we were, they didn't have the same intensity.
"I'm not saying we can keep that up all season, but when you start with a hard run of games, as we do, you have to make sure you are as well prepared as possible. The fitness of the players at the moment is excellent."
Of the younger players at Old Trafford, French midfielder Paul Pogba has drawn some comparisons with the way Patrick Vieira was during his younger days.
The veteran boss is quick to remove the pressure of expectancy off the player's shoulders, but admits that he will get a few chances this season.
"That's just because of his height and build," said Sir Alex. "You don't want to be putting the lad under that sort of pressure yet, but he's got all the equipment all right.
"He's strong and athletic and he's almost ready to be considered. We are just trying to work on his distribution.
"He has been playing a short passing game and we think he could do with a bit more range. We will be giving him opportunities this season because if you don't use good players you end up losing them.
"We can't hold him back, and wouldn't want to do anyway."
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