Here we take a look at the timeline in which we saw the Baggies go through sizeable changes, but ultimately fail in their attempt to stay in the Premier League.
West Brom 0 Leicester City 3 - Back with a bump
The Baggies were handed a tough start to their life back in the top flight, welcoming Leicester City to The Hawthorns.
Despite the obvious excitement amongst fans and players alike heading back into the Premier League, it was a game to forget for Albion.
The Foxes dominated the game, and goals from Timothy Castagne and a spot-kick brace from Jamie Vardy ensured West Brom started with a bump.
West Brom 3 Chelsea 3 - The first point
It took almost a month for the Baggies to register their first point of the campaign, but despite the achievement it could've been all three for the Baggies as they hosted Chelsea.
Slaven Bilic's side pounced on the Blues' mistakes and fired their way into a 3-0 half-time lead with Callum Robinson at the double.
However, Albion simply couldn't hold onto their lead, and after Mason Mount scored Chelsea's first of the night with more than half an hour remaining, the comeback script was written.
Callum Hudson-Odoi added a second, and Tammy Abraham ensured Albion could only have a point after he netted in stoppage time.
The point was enough to get the side out of the bottom three.
Acrimony over transfer dealings
Albion's summer transfer business was far from ideal, although it did bring plenty of positivity from fans at the time.
The likes of Grady Diagnana, Filip Krovinovic, Callum Robinson and Matheus Pereira returned to the club, whilst Conor Gallagher joined on-loan for the season.
Bilic had expressed some frustration with the dealings though, questioning the amount of time it took to bring Krovinovic in, and pushing for the signing of Karlan Grant as his main strike option, which also took a lengthy period to get over the line.
Grant didn't sign until mid-October, whilst the departure of Ahmed Hegazi raised eyebrows following comments suggesting Bilic wanted to keep the defender at the club.
West Brom 1 Sheffield United 0 - The first win of the league season
October wasn't particularly pretty, and it wasn't until the final few days of November that the Baggies managed a victory.
Bilic's side got themselves ahead through Conor Gallagher's strike, and then rode their luck to get three points at home against the Blades.
Sam Johnstone pulled off a string of saves, whilst George Baldock and Lys Mousset both missed golden chances as Albion held on.
Bilic described the result as 'crucial' for his side's confidence.
Man City 1 West Brom 1 - The strangest night of the season
Unsavoury defeats had some fans calling for Bilic to leave in December, most notably after Albion were thumped 5-1 at The Hawthorns by Crystal Palace.
However, the Baggies players showed their mettle against Manchester City, who couldn't stop the Midlanders earning a point at The Etihad.
The result was a big talking point, but nowhere near as big as the bombshell reports which emerged after full-time suggesting that Albion were to sack the man who got them up.
Fans and pundits alike were confused following such a good result against the Cityzens.
Slaven Bilic gets the sack
Following the draw with City, reports in the national press were confirmed as Slaven Bilic was sacked by Albion's board.
The side were just two points from safety, but cracks reported between Bilic and and his superiors were clear to see and the club made the move to sack the Croatian.
Bilic had built plenty of merit with supporters, having achieved promotion ahead of schedule, but just three months after getting the club started in the top flight, the former Hammers boss was without a job.
Sam Allardyce appointed at The Hawthorns
It didn't take long for Albion to name Slaven Bilic's replacement, and that came in the form of ex-England boss Sam Allardyce - who was announced the very same day Bilic's sacking was confirmed.
Sporting and technical director, Luke Dowling, said following the appointment: “In Sam we have a man who has a proven Premier League pedigree with a track record of improving every club he has managed."
“We believe and, more importantly, Sam believes we have a group of players that have the quality needed to give the club its best chance of Premier League survival.”
Big Sam's slow start
Unfortunately for Albion, there was no bounce to come from their appointment of Allardyce - with his first game in charge a timid 3-0 defeat at home to Aston Villa.
This was followed up by a point at Anfield, before more heavy defeats came their way.
The Baggies were comprehensively beaten by both Leeds and Arsenal, conceding nine goals over the two fixtures.
Those results left Albion 19th, six points from safety - and with a -28 goal difference.
Blackpool 2 West Brom 2 - Out of the Cup to lower league opposition
Things weren't going well in the top flight, and it didn't get any better in the FA Cup for the Baggies.
They travelled to Blackpool in the third round, only to get dumped out on penalties to a side in League One.
It was a sign of the low confidence swirling around the club at the time, along with the slow take-up the players had shown in getting Big Sam's methods down - albeit with minimal time on the training pitch working against them.
Wolves 2 West Brom 3 - Derby day triumph
Things turned in one of the club's biggest games of the season, away at Wolves.
It was the first meeting between the sides since Albion's 5-1 win over their bitter rivals back in 2012, and it didn't disappoint for fans watching from home.
Two Matheus Pereira penalties either side of Semi Ajayi's goal had seen Albion overturn a 2-1 defecit at half time, and clearly boosted confidence around the club.
Big Sam's side were still in 19th, but the win lifted spirits and hinted that the side had turned a corner.
New signings invigorate the fans
The confidence built from the side's win over Wolves was dampened once again by an unfortunate defeat to West Ham, and a thrashing at the hands of Manchester City.
A 2-2 draw with Fulham, in which Albion had led with 15 minutes to play also saw fans questioning the chances of survival.
However, the late signings of Mbaye Diagne, Ainsley Maitland-Niles, Okay Yokuslu - joining Robert Snodgrass proved just the injection needed under Allardyce.
Their signings showed fans just what the side was missing, and had they come in sooner, many would feel that Albion could've stayed up.
Sheffield United 2 West Brom 1 - A dark day in Sheffield
One of the darkest days of the season came in opening days of February, as the Baggies travelled to Bramall Lane for a huge relegation six-pointer with the Blades.
New striker Mbaye Diagne earned his first start for the club having come on against Fulham previously, but couldn't inspire the team to any kind of result in Yorkshire.
Albion had taken the lead in the first half, but goals from Jayden Bogle and Billy Sharp cast the visitors to defeat.
That result saw Albion nine points off 17th place, and just a solitary point ahead of Chris Wilder's struggling side. Relegation was now a real possibility.
Points which should've been more
Performances needed to improve for Albion, and they did through February - but results simply didn't match.
Allardyce had his side well-drilled and saw the likes of Yokuslu, Diagne and Maitland-Niles all settle into their roles - but points they arguably deserved didn't materialise.
Albion lost to Spurs 2-0, but saw draws against Manchester United and Burnley come their way, when they deserved to be registering victories.
At Turf Moor, Albion did all but score, despite being reduced to 10 men after Semi Ajayi was sent off for denying a goalscoring opportunity for the hosts.
A win against Brighton helped the cause, but the Baggies went on to lose at Everton when a draw would've been fair, whilst only logging a point at home to a struggling Newcastle United side.
Crystal Palace 1 West Brom 0 - A big hammer blow
One big blow to Albion's survival hopes came at Selhurst Park.
Having been heavily beaten by the Eagles previously, Albion now came to the capital looking to log what could've been a crucial win. But they left without a point courtesy of Luka Milivojevic's spot kick.
The games were beginning to run out, Albion had just nine left, and were eight points behind 17th place with a vastly inferior goal difference.
A duo of big wins to trigger a run?
The Baggies needed wins to save themselves, and two of them came in unexpected fashion.
Travelling to Chelsea, rejuvinated under new boss Thomas Tuchel, few gave Albion a chance of scoring, let alone winning. However, Big Sam's side shocked fans, players and pundits alike with an astonishing 5-2 win in London.
Having fallen behind against the run of play, the Baggies saw their opponents reduced to ten men and made them pay for it. Two goals in first-half added time gave them the lead, and they following with further quality in the second half to see off Chelsea in style.
After that, Southampton came to the Black Country and were soundly beaten as Albion got on a roll.
The only issue? Sides around the Baggies were themselves picking up points. More wins were needed to keep the greatest of escapes alive.
Derby day draws end the hopes
With the Baggies still eight points from safety, they faced a duo of derbies to try and continue their run.
Villa welcomed the Baggies first, but it was late heartbreak for the visitors, who led in added time only to see Villa equalise after a mistake between Kyle Bartley and Sam Johnstone.
Following that, when a win was most needed against an out of sorts Wolves side, Albion could only muster a point in an encounter remembered better for the weather than the quality on the pitch.
Performances had improved, but it had all come too late. Allardyce admitted after the Wolves draw that his side needed 'a magic miracle and fairy dust' to stay in the Premier League.
The drop was confirmed by a 3-1 defeat on the road at Arsenal.
Goals from Emile Smith-Rowe, Nicolas Pepe and Willian ensured the Baggies would be playing Championship football next season.
They didn't go down without a fight though, but questions now turn to the future of not only Sam Allardyce, but also a number of key players who impressed on the Premier League stage.
Immediately following the defeat, Allardyce would not be drawn on his future, with talks due to be held with higher ups regarding decisions to be made ahead of next season.