West Bromwich Albion have only lost at home three times this season
West Bromwich Albion eased back to the top of the Championship table as they put a big dent in Derby County's hopes of a play-off place.
A goal in each half from on-loan Grady Diangana and young Irish defender Dara O'Shea lifted the Baggies back above Leeds United.
Slaven Bilic's side are now two points clear of Marcelo Bielsa's Whites, who host relegation-threatened Stoke City at Elland Road on Thursday.
But, most importantly in the race for automatic promotion, they have restored their advantage over third-placed Brentford back to five points.
Derby, previously unbeaten since the season restarted on 20 June, suffered their first loss in seven league matches. And, on a night when driving force Wayne Rooney was substituted, defeat came at a further cost with Louie Sibley's late dismissal.
The 18-year-old's red card, for apparently attempting to kick his way out of a tangle of legs, was Derby's sixth this season - the most in the Championship.
But, although a three-game ban for violent conduct awaits, the Rams may well appeal, given how innocent the incident looked on the television replay.
Derby are back in action in one of Saturday's two lunchtime kick-offs at home to Brentford, while Albion go to Ewood Park to face another play-off chasing side, ex-Baggies boss Tony Mowbray's Blackburn Rovers.
Albion looking fit for the top flight
After emerging shakily from football's three-month Covid-19 pandemic shutdown with a goalless draw at home to local rivals Birmingham City and 1-0 defeat at Brentford, Albion have now well and truly regained their momentum.
They have now won three in a row, scoring nine goals in the process - of which Matheus Pereira has been the architect of most.
Once again, he set up another to help win this game, according to Opta taking his tally of assists to 16 for the season - comfortably now the Championship's best.
It is no wonder that the first piece of business Albion did after the restart was to make his move from Sporting Lisbon permanent.
Diangana shows his class
Kamil Grosicki started it all with a superb pass to pick out Diangana's run into the left side of the Derby box.
The recalled West Ham United loan man still had a lot of work to do before registering his seventh league goal of the season, but he finished superbly, rounding keeper Ben Hamer to slide in a low left-footed shot off the far post from a tight angle for his second goal in as many games.
Albion could have doubled their lead by the break but top scorer Charlie Austin's half-hit volley was brilliantly turned round the post by Hamer. Then, from the resulting corner, Baggies defender Semi Ajayi turned and shot in one movement, but just wide.
It then took a great cover tackle by the backtracking Rooney to deny Pereira and keep the Rams in the hunt.
They had one chance when Sibley shot wide, before surviving a penalty shout when Pereira went down in the box very easily from Matt Clarke's mild shove.
And, after a 97th-minute derby equaliser against Nottingham Forest on Sunday, they still nursed hopes of a point until 13 minutes from time.
They conceded a needless corner when young defender Lee Buchanan clattered into his own goalkeeper, forcing him to spill the ball over the line.
And, from Pereira's set-piece, O'Shea peeled off his marker to time his near-post run brilliantly, materialising in front of the flat-footed Buchanan to power in a near-post header past Hamer.
Derby finished with 10 men for the third time since the restart, but the game was gone by then.
West Bromwich Albion head coach Slaven Bilic:
"We were magnificent. It's not only the three points, it's the performance which gives you belief and confidence.
"We played with a very offensive but the way we defended was great. Everyone did the job.
"To leave Derby, in the form they are in, with nothing requires not only patience and quality. Everything was there.
"The guys below are putting the pressure on us and Leeds. We don't put the pressure on each other but it's nice to be back on the top of the table."
Derby County boss Phillip Cocu:
"That is no red card. I think we will appeal. At first, I wasn't sure as it was on the other side of the pitch. But, when I saw the clip it was 100% no red card.
"If he gets a suspension, for me, it would be unbelievable.
"I know what he (Rooney) was annoyed about. The same as we were all annoyed about. That is how the referee was leading the game, or not leading the game. A lot of decisions were very doubtful.
"Everybody can have a good or bad day, like us as players or managers, but sometimes you also have to take responsibility if it was a nightmare."
