The Light Blues were punished for their early profligacy as the French side raced out to a three-goal advantage, growing into the contest as the match wore on and reducing the arrears through a well-taken Paul Nsio strike.
Speaking to RangersTV after the match, McCallum reflected on the challenge which Monaco posed in Govan: “We went up against a strong opponent today, which we always knew would be the case.
“We watched their recent game in the Premier League Cup against Liverpool, so we had an idea of what the game was going to be like. They obviously added players that were too old for the Premier League Cup which we knew in advance.
“I thought we started well and had two good moments to go ahead but, unfortunately, we didn’t take them. The most frustrating part is the goals that we lost came from key bits of what we felt Monaco were going to be like.
“We knew they were really good in moments of transition when you turn the ball over, and that was the case with the three goals that we lost, so it presents you with a different challenge when that happens in quick succession.
“However, I must say that the reaction from the group was really good; getting a goal back before half-time helped. The second half then came down to being good in both boxes, which we were in our own penalty box, but we need to be more clinical in the attacking box.
“If you look at how quickly the goals happened, it was a quite short spell within that. Naturally, individuals can feel a little bit sorry for themselves, and that was one of the conversations at half-time; when we get the goal back we don’t need to feel that way.
“We felt the game was fairly even in general play, and that we had as many good bits of possession that they had.”
Hundreds of Rangers supporters braved the extreme weather in Scotland this afternoon to show their support for the young side, and McCallum believes it’s an experience which the players can utilise going forward.
He added: “Any opportunity to play at this stadium for the lads is always a brilliant opportunity. A few more of them got an opportunity today because some of the boys that perhaps would have been involved have been part of the first-team training group today.
“At the same time, it’s beneficial for younger players to come into this environment and play against that level of opposition, feeling the pressure and stress involved in these games at this stadium.
“It’s important to enjoy it, but also be disappointed that we’ve not been more competitive in terms of the scoreline.
“We know we performed at certain aspects of the game that show we can build belief in these environments.”