Rangers ran riot at Vicarage Road, as goals from Martin Rowlands (2), Damion Stewart and Akos Buzsaky clinched a stunning 4-2 victory against Championship front-runners Watford.
The R's stormed into a three goal lead at the break.
Rowlands opened the scoring from the spot, before he turned provider to set up Stewart who headed home to make it two.
The outstanding Rowlands capped a cameo individual display with a third from Angelo Balanta's threaded through ball, and although a Lee Camp own goal temporarily allowed the Hornets back into the tie early in the second period, substitute Akos Buzsaky guaranteed the win eight minutes from time.
Remarkably, there was still time for R's old-boy Danny Shittu to notch a late second for the Hornets, but it was Rangers' day - and how!
R's First Team coach Luigi De Canio made wholesale changes for the trip to Vicarage Road.
Under-18 hot-shot Balanta came in for his full first team debut, while Dexter Blackstock, Marc Nygaard and Stewart all returned to the starting XI.
Rowan Vine, Buzsaky and Simon Walton all dropped to the bench, while Mikele Leigertwood was absent, at the start of his four match ban.
Watford boss Adrian Boothroyd left Marlon King out of the starting line-up, while former R's defender Shittu also had to make do with a place on the substitutes' bench.
In a frantic opening, it was Watford who spurned the first opportunity in the fourth minute.
Nathan Ellington rose unmarked at the back post to meet Jobi McAnuff's cross, but his header lacked power and direction, as it trickled past Lee Camp's left hand upright.
Despite the Hornets' fast start, it was Rangers who opened the scoring in the 13th minute, after referee Mr Foy awarded a penalty.
Balanta's fine through ball landed in front of Blackstock, who was sent crashing to ground by Jordan Stewart inside the box.
Rowlands stepped up from 12-yards and made no mistake, sending Richard Lee the wrong way, for his third goal of the campaign.
Watford should have been on level terms six minutes later though, only for Ellington to blast high and wide from eight yards out.
At the other end, Blackstock's scuffed volley was tipped wide by Lee, but there was nothing the home custodian could do to prevent the visitors from doubling their advantage from the resultant corner.
Rowlands' set-piece was flighted towards the edge of the six-yard box and Stewart rose unchallenged to glance his header in off the underside of the bar.
The home faithful were silenced, but the same could not be said for the supporters in the away end, who immediately broke into a vocal rendition of "2-0 to the Billionaires."
Lloyd Doyley was the recipient of one of the craziest bookings of the season as the half reached its conclusion.
The Hornets full-back appeared to hear a whistle as he retrieved possession inside his own half and inexplicably picked the ball up. Mr Foy had very little choice but to book the player, who was perhaps lucky to stay on the park, having thrown the ball away too.
Rangers finished the half with a flourish, as Rowlands bagged his second of the match to sensationally put the R's 3-0 up at the break.
The goal had class stamped all over it, as Adam Bolder, Nygaard and the tricky Balanta exchanged intricate passes deep inside the Watford half, before Rowlands took one touch to control the ball and then thrashed a fearsome left footed drive past the sprawling Lee.
Undeterred, the Hornets came within a lick of paint of pulling a goal back in the 43rd minute, when Lee Williamson smashed a 20-yard strike off the post, before Camp smothered the ball to safety.
Buoyed by the introduction of Shittu at the break, Watford pulled a goal back in rather bizarre circumstances in the 52nd minute.
Damien Francis rose tallest to meet McAnuff's corner and as Zesh Rehman attempted to hack the ball off the line, the unfortunate Camp saw the ball ricochet off his foot and into the back of the net.
Rowlands' performance went from strength to strength as the half progressed, with the combative midfielder leading by example alongside the ever-efficient Bolder.
De Canio made his first change of the afternoon soon after, as Vine replaced Gareth Ainsworth, whose first half head injury led to him wearing a Terry Butcher style bandage for his hour long stint.
Boothroyd responded by throwing on King, and the master poacher nearly made an immediate impact.
Darius Henderson's lay-off fell invitingly for the Watford number nine, who fired a rising shot inches over the angle of post and crossbar.
Camp was in the right place, at the right time, to deny King again in the 78th minute, before Buzsaky put the icing on the cake for the R's with a fourth goal three minutes later.
A neat passing move eventually saw the ball bounce to Rowlands, who played in the Magical Magyar.
Buzsaky's sublime close control saw him drag the ball past Lee, before he calmly slotted the ball home from an acute angle.
Shittu ensured a nervy finale when he volleyed the ball past the exposed Camp to make it 4-2, but it mattered little, as the R's clinched a handsome away victory, at the home of one of their nearest rivals.
Watford: Lee, Jackson (Shittu 46), Stewart, DeMerit, Francis, Henderson, McAnuff, Doyley (O'Toole 80), Williamson, Ellington (King 69), Smith.
Subs: Mariappa, Ainsworth.
Scorers: Camp (o.g) 52, Shittu 85
Bookings: Doyley 34, Smith 75
Red Cards:
QPR: Camp, Barker, Stewart, Bolder, Blackstock, Ainsworth (Vine 63), Rowlands, Malcolm, Rehman, Nygaard (Walton 92), Balanta (Buzsaky 74).
Subs: Cole, Moore.
Scorers: Rowlands 13 (pen) & 40, Stewart 29, Buzsaky 82
Bookings: Nygaard 44, Barker 60, Bolder 87
Red Cards:
Referee: Mr C Foy
Attendance: 18, 698



















