A double from Umaro Balde and goals from Kane Ritchie-Hosler, Ross McCausland, Chris McKee and Malcolm Ebiowei secured the three points for the Gers.
Speaking to RangersTV after the game, McCallum said: “We are naturally pleased we have been pushing the players in recent weeks to try and get back to the levels that we showed earlier in the season and I think the first half especially is as well as we have played all season.
After a Scottish Youth Cup semi-final defeat to Aberdeen two weeks ago, McCallum said they knew they had to get off to a good start this afternoon.
He continued: “It was important to set the tone, we came up here two weeks ago and Aberdeen beat us and the first-half last time was difficult.
“We knew the levels they would try and achieve and we know we had to go beyond that.
“The message now is that this what you can achieve, it doesn’t happen by turning up to the game on Friday its done during the week at training.”