Kyle Hurst scored an opportunist goal in the 19th minute which ultimately proved decisive.
And even though Forest had a man sent-off after the break for a reckless tackle, Blues remained worthy of the points regardless.
"It was a very complete performance from the boys," said Robinson, Blues Lead Professional Development Coach.
"We had been working on a few things with them. We changed the system, we went to a 4-2-3-1 going to a 4-4-2 when we were being aggressive and pressing.
"I thought they took everything that we have been doing in training on board and it was an excellent performance from start to finish."
"Forest are normally an aggressive side, very big, powerful," Robinson added. "We competed with them from the word go. We didn't let them get a foothold in the game.
"We were patient when we didn't have the ball and when we did have it we were very direct and positive, we got at them.
"Our football at times was really good to watch. We kept it, moved it quick. It was one of those games when it could have been more. But 1-0, a clean sheet for the boys - thoroughly deserved."
Hurst's goal came after he intercepted a pass out of defence. Hurst ran and dribbled round the centre-half, then cut back on the same player near the byline as he slid in to try and recover before sticking a right-footer past the 'keeper.
Soon after Hurst cut inside from the left and cracked an attempt that thudded back off the post, following Oumar Traore retrieving Marcel Oakley's cross and laying the ball to him.
Josh Dugmore made a miraculous goal line clearance, from a Forest free-kick, hooking the ball over his own head and onto the underside of the crossbar and away.
Towards the end, Blues earned the ball back deep in the visiting half that enabled Alfie Chang to slide a pass to Josh Williams, whose cross was nodded wide by Amari Miller.
And then when Hurst weaved his way down the left and centred for Miller, in the box, there was another good chance but his shot was charged down and the follow-up header by Remi Walker was cleared away from the line.
At the death, Forest spurned a chance to equalise by heading straight at Aaron Clayton from a cross stood up nicely behind the defensive line.
Robinson commented: "The boys work extremely hard, week in, week out.
"They get a lot of information thrown at them. They are young, they are understanding the game still and when you explain things to them sometimes they are away with the fairies, they can't quite take it on board!
"No, this week they listened, did everything that was asked and - do you know what? - this was the first time I have seen them together as a group where they were sticking up for each other, putting in tackles, supporting one another. It was great to see."
Wideman Hurst was a regular for the Under-23s last season but has been on Under-18s duty so far this campaign. That is something he has dealt with well, said Robinson.
"Yes, it is difficult for him but I can relate to it in that sense. I had it done to me when I was a young lad growing up.
"I understand his frustrations, but you have got to talk to these boys, explain to them. You have to keep them level-headed and keep them in the game.
"And for me he has been exceptional. His attitude has never changed from the minute he was told he had to come back with us. He has given our lads a lift when he plays as well because of the type of player he is, he is very comfortable on the ball and is very positive when he drives at defenders. And he takes us further up the pitch.
"He has been a real joy to have around and hopefully we won't have him all the time as from a development point of view he needs that challenge of 23s football again. But that's a decision as a group of staff we will sit round and discuss. But at the moment Hursty has been a real good positive for us to have around the group."
Blues gave a competitive starting debut to 15-year-old Cianole Nguepissi at centre-half.
"Cianole, who came up from the Under-16s, I thought was excellent, too," said Robinson.
Blues: Clayton, Oakley, Djurovic, Chang, Kinina, Nguepissi, Murray (Walker 71), Dugmore, Traore (Miller 52), Williams, Hurst.
Subs (not used): Rouse, Craig, Wakefield.