Goals from Alex Lowry and Chris McKee gave Rangers the points in difficult conditions as heavy rain fell for the 90 minutes at The Hummel Training Centre.
Rangers had an effort after eight minutes as Harris O’Connor played the ball through to Ciaran Dickson who turned well before getting a shot away but his effort was just wide of the target.
Shortly after Ross McCausland worked well down the right before getting a dangerous cross across the face of goal which was turned behind for a corner by a Kilmarnock defender.
Matt Yates came close on the 25th minute after he worked his way to find space in the box to get an effort away but it was straight into the arms of the visiting keeper.
The best chance of the half so far fell to Rangers just before the half-hour mark as Ross McCausland fired a shot towards goal which took a deflection forcing a good save from Kilmarnock’s goalkeeper.
Just a minute later McCausland again came close to opening the scoring as he got on the end of a cross from Adam Devine but his left-footed effort was just wide of the target.
Five minutes before the break Kilmarnock had a chance as a free-kick was curled towards goal by their number 10 but it was saved by Lewis Budinauckas.
The young Gers got the break-through just before the break as Ross McCausland’s shot was parried away by the goalkeeper but landed in the path of Alex Lowry who made no mistake is firing a powerful shot into the back of the net.
Rangers came close to adding a second early in the second half as good play resulted in the ball being playing out wide to Harris O’Connor who put a cross across the face of goal but McKee couldn’t get enough of a touch to edge it past the keeper.
The 18’s were two ahead on the 65th minute as Aaron Lyall found Chris McKee who was making a run into the box with the forward firing a low shot across goal to beat the keeper.
Rangers’ Matthew Henderson test the keeper shortly after as he got on the end of a ball from Kane Ritchie-Hosler, but the Kilmarnock number one done well to block his shot.
David McCallum’s side saw out the dying stages of the game with 10-men as Kane Ritchie-Hosler had to come off after taking a knock.
Rangers: Budinauckas, O’Connor, Devine (Muir, 79), King, MacKinnon (Henderson, 64), McClelland, McCausland (Lyall, 64) Dickson, Yates (McKee, 53), Lowry (Balde, 66), Ritchie-Hosler. Subs: Hogarth, Muir, Fraser, Balde, Lyall, McKee.