Certainly bodes well for the future, in fact the present as so many of our u21's have either played or been on the bench for the 1st team.
If you dig a little deeper only two of West Hams team yesterday have served their 1st team as far as i'm aware and that goes for the the other big boys as well such as Utd and Liverpool.
As a 15/16/17 yr old at Saints you surely can't help but be driven knowing you'll be given the chance if you're good enough, a delight to see.