The Spireites played out a 0-0 draw with the Portuguese outfit but looked strong defensively as well as creating a few chances.
Caldwell admitted it was always the plan to work this week on being defensively solid when the opposition was in possession.
“A totally different challenge to what we’ve faced so far and one of the reasons we’ve come out here was to experience that,” he said after the game in Portugal.
“I thought our shape, work rate, understanding of what we had to do was fantastic because they were technically very good, they were sharp and moved the ball very quickly.
“They posed us problems but didn’t create too many clear cut chances if any.
“We could have been a little better on the counter attack and made that first, second pass a little crisper to get ourselves out and give them problems.
“It’s something we’ve worked on recently.
“Most of the focus last week was how we hurt teams and control the ball, this week we’ll try and focus on how we are off the ball.
“We played a little deeper, we didn’t play as high press as we have been and it gives us options to play different ways with and without the ball.”