Leeds 4 West Brom 0 - Report and pictures
If the reverse fixture between these two sides was a turning point in Albion's season, this was a body blow that may have undone all that work.
The Baggies dismantled Leeds 4-1 back in November, but that felt a long time ago at Elland Road, when it was Darren Moore's men left picking up the pieces of their psyche after an even more one-sided defeat.
It may have been third versus fourth at kick-off, but there was a mighty chasm between these two sides that suggests one is still in the hunt for the top two and the other may have to settle for making sure they finish in the play-offs.
Albion had an extra three days than their hosts to prepare for this game, but they looked like startled deer in headlights when faced with the bright white tops of Marcelo Bielsa's intense pressing side.
They fell behind just 16 seconds into the match - despite kicking off - and never once looked like regaining parity.
The 4-3-3 that worked so well at The Hawthorns was rendered redundant here by a pedestrian midfield with actors either too old or too young to cope, and it is now surely time for a rethink.
Moore managed to stop a pitch invader when the third goal went in, but his side were unable to stop much else.
Albion's head coach made two changes to his side. He replaced the injured Kieran Gibbs with Tosin Adarabioyo, who looked out of place at left-back and was partly at fault for both first-half goals.
Hal Robson-Kanu replaced the injured Matt Phillips, and even though he gave Albion a physical presence up front, he couldn't stem the white tide.
Bielsa named the same line-up as Tuesday night, when Leeds lost to QPR, but instead of looking like a team who had played midweek, they flew out of the tracks like a greyhound on speed.
Albion couldn't have got off to a worse start if they tried. Jay Rodriguez passed the kick off back to Gareth Barry, who clipped it forwards towards Robson-Kanu.
He was beaten in the air and with Mason Holgate pushed up, Leeds raced away down the vacant flank.
They squared it to Pablo Hernandez, who was given too much time by Tosin Adarabioyo to find the top corner, sending Elland Road delirious after just 17 seconds.
Once again Albion had handed the initiative to their opponents early on.
Baggies academy product Tyler Roberts nearly made it two ten minutes in, but he diverted the goalscorer's little slipped through ball straight at Sam Johnstone.
Leeds were slicker, faster, and hungrier for the ball, and their intensity was carving through Albion's pedestrian midfield too easily.
The Baggies were relying on out balls to Robson-Kanu, who was winning free-kicks with his back to goal.
They were trying to fight their way back into the game, but they were being swarmed time and time again by men in white.
Two minutes before the half-hour mark, Patrick Bamford added a second when he timed his run perfectly and was found by a lovely reverse ball from Roberts.
Adarabioyo was playing him onside from left-back and he kept his cool to slot past Johnstone for his 11th goal in his last 16 Championship starts.
It was nothing less than Leeds, nor Albion for that matter, deserved.
A few minutes later Kiko Casilla was finally called into action in the Leeds goal, but he comfortably tipped over Jay Rodriguez's first-time long-range effort.
There were signs of fight, particularly from Mason Holgate, who was flying into tackles recklessly. But few signs of quality.
The first half ended with another chance to Leeds. Albion had been outran, outpassed, out-tackled, out-thought, and outplayed.
Incredibly, there were no changes at half-time in either personnel or system, but Albion started the second half better than the first.
Robson-Kanu nodded Gareth Barry's free-kick over the bar after Casilla came and missed it as the Baggies finally enjoyed a spell of pressure.
It didn't last long. Johnstone was the next keeper called into action, saving down low to his left after Roberts had found Mateusz Klich in the box.
Albion were still second best in midfield, and Barry was given a final warning by referee Tim Robinson after too many fouls, forcing Moore to take him off for James Morrison.
Shortly after the hour mark, Bamford wrapped up the points with his second and Leeds' third.
Once again the Baggies lost the ball in the middle of the pitch, allowing the hosts to race away at speed.
Bamford peeled off to the left, and even though his shot was deflected slightly, beating Johnstone at his near post, it was a fair reflection of the hosts' dominance.
Sam Field and Jefferson Montero were also introduced, but it was too little late.
The only concern of the final 10 minutes was whether Leeds could find a fourth, and truly avenge that defeat at The Hawthorns four months ago.
Klich shot from range, as the hosts' intense pressing continued until the final minute.
They eventually found it in injury time, when Ezgjan Alioski tapped home from close range after Albion were picked apart again.
On the basis of this, only one of these teams will be challenging for the top two come May.
Albion are now six points off the top two after losing both of their promotion six-pointers in the space of six days.
They could fall even further behind over the weekend but it's the psychological damage of this defeat which could be even more worrying.
Key moments
01 GOAL LEEDS - Hernandez fires a rocket into the top corner to give Leeds the lead after 17 seconds.
28 GOAL LEEDS - Bamford keeps his cool to slot past Johnstone after being found by a cute ball in behind.
63 GOAL LEEDS - Bamford nets his second after Leeds win the ball again in midfield.
90+2 GOAL LEEDS - Alioski finishes the game with a late finish.
Man of the match
Tyler Roberts - Proved why Albion shouldn't have let him go with a performance full of energy and creativity.
Position in the table
4th - with 60 points from 35 games.
Teams
Leeds (4-1-4-1): Casilla; Ayling, Jansson, Cooper (c), Alioski; Phillips; Hernandez, Roberts (Shackleton 90), Klich, Harrison (Dallas 77); Bamford.
Unused subs: Peacock-Farrell, Douglas, Berardi, Brown, Gotts.
Albion (4-3-3): Johnstone; Holgate, Dawson, Hegazi, Gibbs; Livermore, Barry (c) (Morrison 63), Harper (Field 66); Robson-Kanu (Montero 69), Rodriguez, Gayle.
Unused subs: Bond, Bartley, Townsend, Murphy.
Referee: Tim Robinson
Attendance: 35,888 (2,150 away)