Another poor West Brom performance saw them fall to 10th, further away from play offs, with their season quickly becoming a disappointing one.
Head Coach Tony Mowbray was relieved of his duties after the game, along with Assistant Head Coach Mark Venus.
Meanwhile, Derby County secured a huge three points in their fight for survival.
Narrowly before the 10 minute mark, Derby midfielder Ebou Adams scored the first of the match, from an early corner.
At the half hour mark, and yet another Derby corner, Jerry Yates doubled the Rams' lead.
Derby were able to capitalise on a poor Baggies performance to keep their survival hopes alive.
Following four substitutions from manager Tony Mowbray, the Baggies decreased the deficit with a goal from Adam Armstrong.
It was Derby that scored the final goal of the game, with substitute striker Nathaniel Mendez Laing getting Derby's third of the day, cementing the all important three points for the visitors.
Story of the match
The game started off relatively calmly, and in the first five minutes neither team created much of a threat.
However, after winning a corner, Derby took the lead in the 7th minute. After poor defending and a lack of marking, Ebou Adams had a clear opportunity for his header to fly past Joshua Griffiths.
Frustrated by a well-regimented Derby defence, no real clear cut chances were coming Albion's way. Midfielder Isaac Price was sending inviting balls into the box but they didn't amount to anything.
This minimal attacking threat was maintained throughout the first half, with all the crosses being well defended by the Rams, with multiple Mikey Johnston attempts being thwarted.
Derby's second goal came from yet another corner. It was poor marking again from the Albion defence, this time Jerry Yates meeting a flick on at the six yard box smashing his shot into the back of the net, passed Griffiths.
The Albion came the closest before half time, with Isaac Price's long range shot curling into the post, dumbfounding keeper Josh Vickers.
Albion created some momentum after half time, amassing multiple chances, with a corner of their own crossed in by Price knocked wide by Tobjorn Heggem.
Manager Tony Mowbray's substitutes had changed the game into Albion's favour, but clear cut chances were somewhat rare.
Albion's goal, albeit a consolation, came through a spectacular through ball from Grady Diangana, finding loanee Adam Armstrong who calmy slotted it past the Derby keeper.
During the final minutes of the game, with Albion pushing men forward, Diangana was possessed in the middle of the park. This set Mendez Laing forward, tipping the ball over Griffiths having an open net to score in.
Who will replace Tony Mowbray?
After several dismal performances, Tony Mowbray's second tenure at West Brom has come to a short end, just like the end of their season.
Mowbray's West Brom had achieved just one win in eight, coming up against Watford in a 2-1 scoreline. These results concluded that the Albion lost their spot in the top six after being surrounded by it all season.
In the most recent run of fixtures, West Brom had lost to other play off hopefulls like Bristol City, Sunderland, Norwich and Coventry, with fans claiming them to be the worst performances all season.
If West Brom appoint well, they may have reason to be optimistic with a manager that will have a full transfer window and pre season ahead of the new campaign.
Can Derby County stay up?
After their win at the Hawthorns today, it is a sign of a much more revitalised form for Derby under new manager John Eustace.
This newfound form had seen them come out of the relegation zone, but not yet safe. They are joint on points with 22nd placed Luton and three points ahead of Cardiff in 23rd and last placed Plymouth.
The relegation battle will carry onto the games at the weekend, and a win could put Derby in a strong position.
