It promises to be an intriguing match-up at New Dundas Park as Lowland League leaders Rose look to register their ninth successive win against a young Ibrox side who are just four points adrift having played two games fewer.
Rose got the better of Rangers' Old Firm rivals Celtic 2-1 in the league curtain-raiser in July and will be desperate to extend their lead at the summit.
However, Horn is adamant tomorrow's visitors are likely to pose their sternest test so far.
"We are looking forward to the game tomorrow and although we have been on a good run, we are under no illusions of how hard this game is going to be," the Rose manager said. "We'll be playing against some real, top young talent and it's a new challenge. You just have to look at how many of Rangers' squad have been on international duty the last couple of weeks to see how much quality they possess.
"Similar to Celtic, it's a bit of the unknown as the Rangers team has been rotated a fair bit from the start of the season, plus you just don't know if the guys coming back from international duty will feature too.
"We have a couple of players missing this weekend which is just the norm at the moment and fortunately the squad has been able to deal with this. If we approach the game similar to the way we did against Celtic and the way we played in the second half of last week, then we are hopeful of causing an upset."
Meanwhile, third-placed Spartans, who are also just four points off the top, travel to play East Kilbride at K-Park.
Dougie Samuel's men have been in fine form but their hosts, who were tipped to challenge for the title before a ball was kicked, have struggled and are languishing in 11th with just four wins out of nine. Spartans will more than fancy their chances of securing another three points.