The Gers bowed out of the competition this evening to Scottish Championship side Queen’s Park having been forced to play 55 minutes with ten men.
It brought an end to an impressive cup run for the Light Blues, who entered the quarter-final stages as the only B Team representative.
Speaking to RangersTV after tonight’s defeat, McCallum reflected: “It’s a talented group with talented individuals.
“We’re trying to win games by doing the right things, but understanding that you need to do other things really well.
“They’ve been really good throughout the whole tournament and they will see tonight as a missed opportunity because they were 1-0 up at half-time and doing quite well.
“They’ve showed what level they can get to throughout the course of the tournament against a mixture of men’s opposition and it’s now about using the experiences they’ve had to take forward and make sure their career benefits from it.
“Everything that they do provides opportunity for learning. We talk about certain habits you can have as an individual when you’re training and playing that are almost non-negotiable.
“It’s not always about you and the ball but you without the ball, and making sure you hit your absolute maximum and get something from each training session. When it comes to game day, that’s just your normal habit.
“That’s what we’re trying to promote, so when it does come down to you and the ball then the other bits are done and that’s the bit which becomes the difference in the game.”
Rangers took the lead on the evening as Cole McKinnon nodded home from Paul Nsio’s delivery.
Indeed, it was a dominant opening half-hour from the away side, who also had chances through Robbie Fraser and 17-year-old Chris Eadie.
On the result, which pivoted on the decision to dismiss Clinton Nsiala for an off-the-ball incident, McCallum added: “I thought Queen’s Park started really strongly, but you expect that against a really strong Championship side.
“But the lads were resilient and made it difficult for them to break us down, and then we started to find our way.
“We had the chance to go 1-0 up through Chris Eadie, then we scored a really good goal from a cross.
“At that point we started to settle down; Robbie Fraser hits the post. We had some really good moments in the first half to put ourselves in a comfortable position.
“After that a couple of things happen which makes the game a little bit more challenging from what it was in the opening 30 minutes or so.”