Alex Ferguson says he has complete faith in his youngsters and says that he is enjoying watching them play.
The young players were instrumental in Manchester United's win over rival City in the Community Shield a couple of weeks ago as Danny Welbeck, Tom Cleverley, Phil Jones, Chris Smalling all shone.
And with veteran plays such as Rio Ferdinand and Nemanja Vidic out with injury they will be called on one again by the club.
United are set to face Tottenham Hotsupr on Monday night and Phil Jones, who is just nineteen years old, will be in central defence while Chris Smalling will play at right back.
Speaking to The Sun the United boss said: "We were always aware we had players who were coming to the end of their careers. That has been on the horizon for us for quite a few years.
"We knew it was going to happen, you don't want it to, but it does and there's nothing you can do about it. Age catches up with us all.
"So we've replaced the players who have left us and we've still players at the club in their 30s, which is a lot of experience.
"It is a very young team at the moment but it's one full of energy and of great ability. I'm enjoying watching them."
"I'm not worried about the young players filling in at the back.
FemaleFirst Helen Earnshaw