The former Light Blues winger is now the player/manager of the side Gers will face in the last eight of the Ramsdens Cup on September 18 or 19 at Ibrox.
Having taken charge at the end of last season once Queens had been relegated from the First Division, he has made a promising start to his career as a coach.
But despite four wins and a draw in five outings so far, Johnston is realistic and accepts his men will be expected to lose when they go to his old stomping ground.
That’s not to say he doesn’t believe they can win, however, and he knows regardless of the outcome that his young pool will benefit greatly from playing at such a prestigious venue.
Johnston, now 38, said: “It’s great for the players and I’m sure all the boys will be delighted with the draw and the opportunity to play at Ibrox.
“Let’s not kid ourselves – it’s going to be a difficult game and Rangers have got top quality players but we’ll not just be sitting back. We’ll try to win but we’ve got to be realistic.
“For us to achieve anything, we’ve got to be at our very best. We’ve got a lot of young players though and it’s a massive opportunity for them.
“They’ve just got to go out there and express themselves. Just to get the chance to play at that sort of venue and against the standard of opposition they’ll face will be good for them.
“Everyone wants to test themselves at the highest level possible and this game gives our squad a chance to do that.
“It’s a good tie for our club financially and it’s good for the fans as well as the players. It’s one we will all look forward to.”
Johnston has only made one appearance this season for Queens and that came at the weekend but it ended badly for him as he was sent off two minutes from the end of a 0-0 draw.
That means he’ll be back to watching from the sidelines this weekend when the Doonhamers host Albion Rovers in Dumfries.
Johnston spent 15 months with Rangers in 2000 and 2001, scoring three times in 26 games before moving on to Middlesbrough.
He has kept tabs on how things have panned out in recent months at Ibrox and is pleased the club is on the up again.
Johnston added: “You see how the fans turn out in their numbers and it has been unbelievable to see such big crowds despite Rangers being in the Third Division.
“You can see how positive everyone has been in terms of getting behind the club and Rangers coming to the SFL has been good for us all overall.”