Leeds United are out of the FA Cup after a deserved 2-1 defeat to Queens Park Rangers at Loftus Road.
Aramide Oteh and Jake Bidwell struck either side of Aapo Halme's first United goal to send Rangers through to the fourth round.
With a keen eye on Friday's crunch clash with Derby County, Marcelo Bielsa fielded a callow team.
The Leeds side in W12 featured a plethora of youngsters - the bulk of them graduates of the club's academy. Indeed, the average age of the team Bielsa selected was a paltry 22.
And United's youthfulness was no match for a more experienced QPR side.
The visitors did threaten to break the deadlock as early as 33 seconds in. Tyler Roberts struck both posts with a venomous shot that somehow failed to find the net. Thereafter, though, the Hoops sought to take control of the match.
Steve McClaren's side began to turn the screw. Eberechi Eze's excellent run and shot from 20 yards drew an excellent parry from Bailey Peacock-Farrell on eight minutes. The United 'keeper was soon in action again to push over Bidwell's header from the ensuing corner.
Moments later, Peacock-Farrell was at the forefront of proceedings again. Bright Osayi-Samuel burst past Leif Davis and onto Eze's looping pass. He bore down on goal with intent, but the goalkeeper was quick off his line to deny him.
Despite Peacock-Farrell's heroics, Rangers would soon take a deserved lead from the penalty spot in the 23rd minute.
They won a free kick in a dangerous position on the left channel. Leeds headed clear, but only as far as Bidwell on the edge of the box. He took an excellent touch into the area before Davis tripped him.
Oteh stepped up and slotted the ball into the middle of the net.
But Leeds hit back almost straight away. Two minutes after going behind, their opponents contrived to gift them an equaliser.
Aapo Halme followed in to score a tap-in after Matt Ingram fumbled Lewis Baker's free kick.
The game promised further goals. Osman Kakay shot straight at Peacock-Farrell after Baker gave away possession. Ezgjan Alioski drove a volley wide at the other end.
The first half ended with Oteh surging forward and firing over the bar. If not for the music blaring around Loftus Road, one might have heard a sharp, collective intake of breath reverberate around the ground.
The start of the second period was not so frenetic. United grew into the match and began to control possession. But their dominance of the ball produced little in the way of meaningful attacks.
In their best move, Jamie Shackleton made a marauding run forward before Jack Harrison found Roberts in the box. Under pressure, he could only toe-poke the ball straight at Ingram.
Thereafter, Rangers upped the ante in search of a second goal. Jordan Cousins hit a blistering shot from outside the box that Peacock-Farrell pushed onto the post. Darnell Furlong then headed over from the resultant corner.
As had happened in the first period, a concerted spell of QPR pressure produced a goal. Leeds's young and inexperienced and fragile defence could not withstand it. It was like a feeble wooden hut trying to weather a raging storm.
A set-piece was again their undoing in the 75th minute. Bidwell, unmarked, met Luke Freeman's corner to glance a header across goal and into the net.
United had equalised a mere two minutes after going behind in the first half. There was no repeat of that. A determined block from Ingram met Harrison's shot from a tight angle following a corner.
Bielsa threw on young striker Kun Temenuzhkov in a bid to salvage at least a draw. But it would be the hosts who came closest to scoring a fourth goal of the match.
Freeman struck an excellent free kick from the edge of the box. It looked to have beaten Peacock-Farrell. But it swerved in the air before crashing against the post. It would also prove the last notable action of the match.
It is unlikely that Leeds fans will greet this defeat, a third in succession, with any great disappointment. It is also unlikely that they will castigate Bielsa for selecting a weakened team. United have their eyes on a greater prize - that of automatic promotion. And this experience will be of considerable benefit to the club's fledglings, who did hold their own for large periods of this match.
Queens Park Rangers just about deserved the victory. They looked especially threatening in the first half. Their dynamic, direct attacking down the flanks caused Leeds a great many problems. In this regard, Eze was most impressive in the first period.
United will now look to Friday night's televised clash against fellow promotion aspirants Derby County. In the meantime, they hope to make progress in the transfer window. Bielsa has made clear his wish that the club sign a goalkeeper and a winger.
Whether we will see any progress on that front is a question of time. What is for certain is that Bielsa has overseen a remarkable period of progression at the club. For Leeds to disregard an FA Cup match as they have done here, with the motive of going after automatic promotion, is a fine representation of the seismic transformation he has instigated.
Leeds United: Peacock-Farrell, Shackleton, Ayling, Halme (Pearce 45’, Temenuzhkov 79’), Davis (Odour 87’), Forshaw, Clarke, Baker, Harrison, Alioski, Roberts.
Unused Subs: Huffer, Diaz, Stevens, Gotts.
Queens Park Rangers: Ingram, Kakay, Furlong, Hall, Bidwell, Osayi-Samuel (Wszolek 86’), Cousins, Scowen, Freeman, Eze (Smith 90’), Oteh (Chair 83’).
Unused Subs: Lumley, Manning, Baptiste, Smyth.
Match Statistics (QPR / Leeds)
Shots: 16 / 9
On target: 10 / 7
Possession: 45% / 55%
Corners: 11 / 9
Fouls: 14 / 11
Match Details
Referee: Geoff Eltringham.
Booked: Kakay, Furlong (QPR). Halme, Baker, Alioski (Leeds).
Attendance: 11,637.
Man of the match: Eberechi Eze (QPR).