Goals from Jake Burger, Oli Lynch and Zack Nelson overturned Teddy Lawrence's first-minute opener as Alan McCormack's Category 3 side claimed the scalp of another Category 2 academy, after the 6-0 demolition of Birmingham City in the previous round.
The Hatters fell behind within the opening minute, when Teddy Lawrence forced the ball home from close range after good work down the right by Kieren Petrie.
Town mounted an immediate response, with Zack Nelson firing over the bar from the edge of the box, but they were level by the seventh minute when Jacob Vickers headed a deep corner back towards goal and Burger flicked it home from close range.
Nelson and Millar Matthews-Lewis both went close before Lynch tapped the Hatters into the lead on 12 minutes after captain Jacob Pinnington had raced down the right and his deflected cross made its way to the striker, who finished from almost on the line.
Rangers keeper Harry Cant made a terrific double stop to prevent Archie Heron from adding a third, then Town stopper Sam Bentley pulled off a brilliant save to deflect Rayan Kolli’s snap-shot onto the bar at the other end.
Bentley had to make a routine save from Samuel Sackey’s 25-yarder on the half-hour, and after a spell of good possession for the visitors, Town went close again five minutes later when Heron curled over the bar, after Joe Johnson had gone on a rampaging run down the left.
Jayden Luker was the first player into referee Dale Wootton’s book for a foul on Guilherme Siqueira with five minutes to go to half-time, with Lorent Talla hitting the resulting free-kick high over Bentley’s crossbar from 35 yards out.
QPR skipper Charlie McDonald was next to be shown a yellow card for a deliberate handball while on the floor to prevent Burger running onto the loose ball, and Rangers needed another Cant save, this time from a Matthews-Lewis piledriver, to keep the score at 2-1 on the stroke of half-time.]
McCormack made a change at the break with Rio Martucci replacing Luker, but it was Rangers who came out of the blocks quickest, Kolli testing Bentley before Shannon Brown was booked for a late challenge on Nelson.
Petrie went close with a twist and angled shot on 56 minutes, after Vickers had seen a header cleared from almost on the line at the other end.
Rangers continued to ask questions as they sought a way back in, with substitute Jabari Christmas bending one just wide of Bentley's left post, before Lynch tested Cant again at the other end with just over 20 minutes to go.
Talla curled a 20-yarder into Bentley's hands on 71 minutes, then the Town stopper got down low to his left to fall on a shot from Christmas from the edge of the box.
The lead was finally extended a minute later when Lynch flicked Jack Bateson's forward ball on, Matthews-Lewis held it up on the edge of the Hoops penalty area and laid it into the path of Nelson to side-foot into the bottom corner.
Bentley dived to his left to push away another effort from Kolli with ten minutes left, then left-back Jake Leahy cut in from the left and fired just wide with his right foot, before limping off through injury.
Rangers sub Sam Bagan headed wide at the far post with a miniute of normal time to go, but the Hatters comfortably saw out six minutes of added time to cap a fine team performance in front of a crowd of just over 1,000 at the Kenny.
Town: Bentley, Pinnington (c), Johnson, Burger, Bateson, Vickers, Heron, Luker (Martucci 46), Lynch, Nelson, Matthews-Lewis (Odegah 73). Subs not used: Hemlin, Odell-Bature, Moffat, Giwa, Hockey (GK)
Goals: Burger 7, Lynch 12, Nelson 72
Rangers: Cant, Siqueira, Leahy (Bagan 82), Brown (Tuck 55), McDonald (c), McCann, Sackey (Christmas 65), Lawrence, Kolli, Talla, Petrie. Subs not used:
Goal: Lawrence 1
Att: 1,005 (154 away)
