West Brom usurped Leeds at the top of the Sky Bet Championship table once more as they recorded a comfortable 2-0 win over 10-man Derby.
A second goal in as many games from Grady Diangana set the Baggies on their way at The Hawthorns (11), with Dara O'Shea's second-half header sealing the three points for Slaven Bilic's men (76).
Derby, who failed to register a shot on target throughout the 90 minutes, were then reduced to 10 men in stoppage-time when 18-year-old Louie Sibley was shown a contentious red card by referee Jeremy Simpson after an off-the-ball incident with O'Shea (90+1).
Although West Brom could be knocked from the summit if Leeds beat Stoke on Thursday evening, they move two points clear of Marcelo Bielsa's men, while the Rams remain three points off the top six with four games remaining.
Bilic's Baggies back in the groove
Wins for Brentford and Fulham on Tuesday night had put pressure on the Baggies to ensure their automatic-promotion push stayed on track and, after an open start, they responded in the best-possible manner.
It was a moment of class from Diangana that did the damage. The on-loan West Ham man collected Kamil Grosicki's slide-rule pass, took the ball beyond Ben Hamer with one touch and squeezed a shot home via the far post with another.
Derby were dominant in possession but struggled in the final third and although a pair of dangerous crosses from Jayden Bogle and Craig Forsyth caused alarm, goalkeeper Sam Johnstone was left almost wholly untested.
Either side of the break, Hamer made two smart saves that undoubtedly kept the visitors in the game. He first pushed an awkward, deflected Charlie Austin shot around the far post, then reacted well after Matheus Pereira had rushed onto a square ball just inside the penalty area.
An animated Bilic was left fuming on the touchline with 20 minutes to play as Pereira was denied a penalty despite an apparent push by Matt Clarke, but within five minutes, O'Shea headed a second after Derby had needlessly conceded a corner.
A Chris Martin equaliser deep into time-added-on salvaged a point for Phillip Cocu's men in Saturday's East Midlands derby with Nottingham Forest, but there was to be no repeat, only a third red card since the restart. O'Shea trapped Sibley's leg between his after being felled and, after the latter forcibly removed it, he was sent off.
Man of the match - Matheus Pereira
As lively as ever, the Brazilian turned in another display that left few questions unanswered as to why many regard him to be the best player in the Championship. In setting up O'Shea's goal, he recorded his 20th assist of the campaign and fourth in just two games.
Should the Baggies be promoted in two weeks' time, the 24-year-old will be a welcome addition to the Premier League.
What the managers said...
West Brom's Slaven Bilic: "Three points at this stage of the season are important but the way we played was fantastic. We played against a team that is in form, a team I like and a team that has a lot to play for and we were excellent in everything. The only thing that was missing was an earlier second goal.
"It's a very nervous end to the Championship season because of the clubs who are behind us and doing well. There's a lot of pressure and it's not easy for the boys but they coped with that excellently today."
Derby's Phillip Cocu: "It was a tough game. In the end, the second game made the decision because it was still quite a tight game towards the end. I had to think about Saturday's game so that's why I took Chris Martin and Wayne (Rooney) off. We have to accept the defeat.
"Of course you play to win, especially when we are still fighting for a play-off spot, but you also have to be realistic. We have to improve."
West Brom face Blackburn at Ewood Park at 3pm on Saturday July 11, with Derby taking on automatic-promotion-chasing Brentford a few hours earlier at 12.30pm, in a game live on Sky Sports Football.