At 37, Ryan Giggs would still rather think of himself some days as more like an 18-year-old with 19 years' experience. But then he sees his younger Manchester United team-mates wearing their "mad clothes", listens to their conversations and cannot help but feel out of the loop sometimes. "It is when they start talking about computer games," he says. "They play something called Black Ops, it goes completely over my head."

The thirtysomethings at Old Trafford have all been watching from the sidelines recently. Giggs, the club's oldest player, has not started either of United's two league games and watched the Community Shield in his suit, not even selected among the substitutes. Michael Carrick has not played a single minute of the wins against West Bromwich Albion and Tottenham Hotspur. Dimitar Berbatov has been restricted to 26 minutes over the course of three matches.

A theme has developed and, with it, there has been a discernible change behind the scenes. Voices that were rarely heard a year ago have become louder, growing in confidence. "A lot of the older players are no longer there," Sir Alex Ferguson says, "so we have a young element in the dressing room who are starting to take control of the place." The manager gives the impression he is enjoying this changing of the guard. "The young players have created a good spirit around the place. There is a perkiness about the dressing room."

The average age of the team against Tottenham on Monday was 23 years and one month, making it the second youngest side Ferguson had ever put out in the Premier League. The youngest was against Hull City on the final day of the 2008-09 season when United were preparing to play in the Champions League final and Ferguson fielded a team of reserves and academy graduates, with four players handed their first league starts and seven substitutes aged 17 to 21.

Monday was a very different occasion – the first home match of the season, difficult opponents, no Rio Ferdinand or Nemanja Vidic – and amid all the praise for the young players a certain amount should be kept back for the manager. It was he, after all, who had the conviction to play Tom Cleverley ahead of Carrick and Danny Welbeck instead of Berbatov. Another manager might have removed David de Gea from the side after his mistakes in the previous matches but Ferguson stayed calm, remembered Peter Schmeichel's early difficulties in England and decided he had to put his trust in a goalkeeper who, at 20, is half the age of the man he is replacing, Edwin van der Sar.

When Ferguson spoke after the match he gave the impression there had never been a single moment when he was worried how the team would cope without the assuring presence of Vidic and Ferdinand. It had always been his way to trust young players, he reminded us, but there had come a point with the current crop where they left him with almost no option. "This group has such fantastic ability," he said, "it forces you to play them, really."

Phil Jones is a case in point, a 19-year-old who gives the impression he is in his 10th year at Old Trafford rather than his 10th week. Sir Bobby Charlton and Paddy Crerand, team-mates from the European Cup victory of 1968, found themselves talking last week and decided they had already seen enough of Jones to pay him what, in United terms, is probably the ultimate compliment. "If you talk to Bobby Charlton," Crerand says, "Phil Jones reminds him of Duncan Edwards with his power and build."

Others will inevitably compare Jones, Cleverley, Welbeck and Chris Smalling with the last group of United players to come off the conveyor belt and create such a frisson of excitement. For now, however, it is probably better to think of the 1995 group of David Beckham, Nicky Butt, the Neville brothers and Paul Scholes (with Giggs a couple of years older) as a once-in-a-lifetime coming together. Cleverley is not Scholes and neither is it fair to expect him to be. But he is doing a fine job keeping Carrick out of the team and, in the process, has turned down the volume, a little, on those who cannot comprehend why the club have not brought in a new category-A midfielder.

Too much can be read into one game, of course. These are only the embryonic stages of the season and Welbeck, for one, can still look raw at times. He is, however, an elusive opponent and the back-heel with which he set up Anderson's goal against Spurs was an exceptional moment of penetrative forward play.

Then there is the emergence of Smalling – a player, like Jones, whose development means the Old Trafford crowd no longer needs to fret unduly about Ferdinand's injury problems. Plus the fact Rafael and Fábio da Silva, at the age of 21, did not even play on Monday. Anderson has already shown in flashes that he can have a productive season and, like Jonny Evans, is still young enough, at 23, to be regarded as promising. Ashley Young is 26, a year older than Wayne Rooney and two years older than Nani. Javier Hernández is another 23-year-old and could feasibly be at Old Trafford for the next decade.

Ferguson has been remarkably unselfish when it comes to putting into place a team that will still be around long after his tenure has ended. "We compete in the present but at the same time build for the future," he says. On both counts, United have reason for optimism.