Derby 3 West Brom 1 - Report and pictures
Albion will meet rivals Aston Villa across two legs in the play-off semi-finals after missing out on a chance to finish third with their first defeat in five games.
The Baggies succumbed to defeat thanks to two goals in three second-half minutes that sealed sixth spot for hosts Derby County, who will meet Leeds in the other semi-final.
Leeds lost 3-2 to bottom club Ipswich Town, which means Jimmy Shan's men would have climbed above them with victory.
But with so much riding on this game for Frank Lampard's men, the hosts looked far hungrier than the Baggies, particularly in a dominant second-half display that laid bare Albion's vulnerability to pace.
An indifferent afternoon turned worse when substitute Hal Robson-Kanu was shown a straight red card for kicking out in injury time, meaning he'll miss the play-off games.
Albion created plenty of chances in the first half, but went into the break 1-0 down thanks to a Martyn Waghorn header.
Stefan Johansen levelled things up two minutes after the restart with a rocket from the edge of the box but that just angered Derby, who peppered the Albion goal afterwards.
But substitute Mason Bennett gave them the lead with 20 minutes to go before a questionable penalty three minutes later wrapped the points up.
It means Derby have done the double over Albion this season, scoring seven goals along the way.
This was nowhere near as one-sided as the previous meeting at The Hawthorns, but it suggests the Baggies remain vulnerable to pace.
Shan made one change to his side, resting club captain Chris Brunt ahead of the play-offs, and replacing him with Jacob Murphy.
James Morrison returned to the bench but Jake Livermore remain sidelined with an ankle knock.
Shan tweaked his system to a 3-4-3 formation, although it looked more like 5-4-1 without the ball.
Both teams started busily, running at their opponents whenever possible, as the football matched the atmosphere in the stands.
Tom Lawrence skipped past a couple of players before a covering tackle stopped Mason Mount from shooting, before Jay Rodriguez fired over up the other end.
Ten minutes in, the striker then slipped Murphy clean through on goal but the Newcastle loanee put his effort wide when he really should have scored.
Lawrence stung Sam Johnstone's palms from range as the match continued to rock back and forth, and Albion's front three were pressing Derby's backline into mistakes.
But 19 minutes in and Derby took the lead with a simple yet clinical goal.
When the ball was whipped out wide to Jayden Bogle, the right-back swung in a wicked cross first time.
Waghorn reacted quickest, ghosting in between a static Kyle Bartley and Craig Dawson to glance a header into the far corner that sent Pride Park loopy.
Albion had a glorious chance to level things up on the half hour mark when Stefan Johansen sent Murphy down the right with a quick-thinking free-kick.
Murphy pulled the ball back to the penalty spot and the person Albion would want coming onto the ball, but somehow Dwight Gayle screwed wide from a central position 12 yards out.
Derby's pace continued to threaten down Albion's left, and it took some strong defending from Kyle Bartley to stop the influential Dwayne Holmes from skipping around him.
Five minutes before the break, goalscorer Waghorn was forced off through injury, to be replaced by David Nugent.
But the Baggies ended an even first half on top, and nearly created another opening when Rodriguez tried to slip Gayle in behind.
Two minutes after the restart and they were level. After a backheel in the build-up from the impressive Ahmed Hegazi, Rodriguez swung the ball over to Johansen on the right hand side.
The Norwegian smashed a left-footed rocket into the far corner that gave Roos no chance and left the home fans stunned while sending the 3,000-strong away end into party mode.
With Ipswich taking the lead against Leeds, the Baggies were one goal away from third, but Derby nearly equalised straight away.
When Nugent was played in behind Bartley, it looked for all the world like the substitute was going to score, but Johnstone rushed out and saved with his legs.
Kyle Bartley cleared a corner off the line before Johnstone saved from Lawrence as the hosts reacted well to conceding.
Shan sent Matt Phillips on for Jacob Murphy, who is unlikely to have forced his way into the play-off team with a mixed afternoon, and Albion improved after that.
But just as the atmosphere started to grow tense inside Pride Park, Derby scored two goals in three minutes to secure sixth spot.
It was substitute Mason Bennett who got the all-important second 20 minutes from time, capitalising after Johnstone's save from Mount hit Hegazi and fell into his path six yards out after some intricate Derby passing on the edge of Albion's box.
Three minutes later and the Rams had added a third when Tom Lawrence danced through the Albion defence with far too much ease before going down in the box under what looked to be minimal contact.
Wilson converted from the spot kick to give Derby a cushion.
But if Middlesbrough were hoping of an Albion fightback, none came, and if anything, the hosts looked like adding a fourth.
Shan took off Stefan Johansen and Kyle Bartley - who had both been booked - to guard against any suspensions for the play-offs.
But in injury time, one of the men he brought on, Robson-Kanu, inexplicably kicked out to earn a red card and end his season early.
It was a stupid end to a disappointing second half, but now thoughts immediately turn to the semi-final with Villa.
KEY MOMENTS
10 Murphy is slipped through by Rodriguez but he puts his shot wide.
16 Bartley booked for bringing down Holmes on the counter-attack.
19 GOAL DERBY - Waghorn glances Bogle's first-time cross into the far corner.
30 Murphy pulls the ball back to Gayle on the penalty spot but somehow he shoots wide.
47 GOAL ALBION - Johansen smashes in an equaliser from the edge of the box.
50 Johnstone saves a one-on-one with Nugent.
70 GOAL DERBY - Bennett gobbles up a rebound after Johnstone saves from Mount.
73 GOAL DERBY - Wilson converts a spot-kick after Lawrence goes down in the box under minimal contact.
90+3 RED CARD - Hal Robson-Kanu sent off for kicking out and will miss the play offs.
MAN OF THE MATCH
Ahmed Hegazi
POSITION IN THE TABLE
4th, with 80 points from 46 games.
TEAMS
Derby (4-1-4-1): Roos; Bogle, Tomori, Keogh (c), Malone; Johnson; Holmes (Bennett 65), Mount, Lawrence, Wilson (Evans 90); Waghorn (Nugent 41).
Unused subs: Carson, Marriott, Macdonald, Huddlestone
Albion (3-4-3): Johnstone; Dawson, Bartley (c) (Robson-Kanu 78), Hegazi; Holgate, Harper, Johansen (Field 74), Gibbs; Murphy (Phillips 60), Gayle, Rodriguez.
Unused subs: Bond, Mears, Townsend, Morrison.
Referee: Tim Robinson
