His young side lost a little bit of ground during the first period and went in at the break 2-1 down, but more than matched their opponents in the second and were denied reward by several outstanding saves by Saints keeper Neil Moss.
"I thought the second half was much improved on the first and lots of ways and, in the end, one or two have done themselves a little bit of justice," reflected Colin.
"But, if I'm being perfectly honest, I think it took a long time to come.
"I spoke to Chris Hughton and he thought the first half wasn't too bad, but their attitude in getting around the pitch and being eager enough to run beyond the person on the ball or run early to give the person on the ball an easier option - it's still got to be better, and it's hard work.
"You could see at the end that one or two were treading water a little bit, but that's to be expected.
"They will come on technically hopefully with all the tactics we impose on them. They've got to come along physically, obviously, because at 17 and 18 they are not physically strong enough to play with the senior boys.
"They will benefit from these games, but they've got to extend themselves from minute one to minute 90, not 45 to 90.
Colin added that results are important for a young team to gain in vital confidence.
"I said beforehand that we wanted a result with a team like this, and we didn't get it again. Whatever you might say, if they get a point from a reserve game they'll feel good about themselves.
"They felt better about themselves after the game with their second half performance. We've got to get into the mentality of the performance and the way they play counts for quite a bit, but we also have to get a mentality of results do count."
Colin Calderwood saluted an improved second half performance by his reserve side, but was disappointed not to get a positive result against Southampton.