Against a strong Eagles outfit, Blues earned a point through Odin Bailey's 73rd minute equaliser in the PDL.
And there was much to admire from the side, who fielded a teenage defence, including debutant Nico Gordon, 17, at right-back/right wing-back.
Blues starting midfield were also all teenagers, including Jude Bellingham, whilst Dani Ruiz, a Spanish trialist, was the oldest outfield player, aged 20.
Palace played Gary Cahill, Victor Camarasa and James McCarthy, their deadline day signings.
"The draw, the result, was a good point," said Calm, Blues Under-23s Head Coach.
"Crystal Palace are a very good team and they had more experience than us, a stronger team than us with their players.
"They had more physicality and I think our team put in a good effort.
"It was difficult in the first-half. Second-half the players trusted in one another more and had more confidence.
"I think we improve when we have more belief in one another, as we saw.
"Towards the end of the match we had clear chances to have won it but a point, it's OK, everything considered."
Calm and assistant Steve Spooner altered Blues shape to a diamond in the second-half and that helped them get a foothold back into the game.
Blues got more players around the ball, more control of possession and more thrust to get forward.
It is that kind of adaptability Calm is looking for from Blues youngsters; the ability to interpret and implement different tactics.
"We have played (in pre-season) 3-4-3, 5-4-1, 4-4-2 and today with a diamond . . . we think all the shapes are good if the players are committed to them, interested in them and want to run, work hard.
"For us, it is important that the players can adapt in a different shape.
"Probably 4-4-2 is the easiest shape to play, but they must be able to switch and be comfortable whatever we think is the best to use in different situations.
"The players don't know what will happen in the future and it is normal in the first team to change the formation to take into account the rival team. These players are Under-23, not Under-12s, so they are expected to learn and improve."
The attitude of the side was spot on. Bellingham, Bailey, Caolan Boyd-Munce and Geraldo Bajrami made their first team debuts at Portsmouth a week ago; Joe Redmond, Ryan Stirk and Ryan Burke were on the bench at Fratton Park.
Bailey was among the substitutes for the visit of Bristol City in the Championship on Saturday.
There was no sense of a come down, or disappointment even, being back on duty with the Under-23s.
"We have had a very good pre-season, in terms of training and games," said Calm.
"All of the players know that, first of all, they have to play and compete with us before they can be considered for the first team.
"If the first team needs our players we are of course very happy.
"But they understand they have to work and improve with the Under-23s. They know this."
Blues Under-23s' attentions now turn to their first home PDL match, against Charlton Athletic Under-23s, at Leamington FC on Friday (2pm).