Millwall went into the match in the top six of the Championship and knew a win on Monday would guarantee themselves a spot in the play-offs.
Advertisement
But in dramatic circumstances, they blew their chance during what was an incredible 45 minutes of football.
The first-half saw the Lions cruise into a 3-1 lead over Blackburn at the Den with two goals from former Sunderland star Duncan Watmore and Oliver Burke's effort.
Advertisement
It looked like that would have set Watmore's old side back and make sure they spend another year in the Championship but drama awaited after the second-half whistle blew.
Joe Rankin-Costello made it 3-2 just minutes after the break before Ben Brereton Diaz delivered two goals of his own on likely his last Rovers appearance to wrestle the match away from Millwall.
Sunderland beating Preston meant that Rovers also didn't finish in the play-offs but that did not stop the travelling fans from taunting the Millwall faithful.
Renditions of, 'I Am Forever Blowing Bubbles', a song sung by West Ham fans at matches, could be heard from the away end at the Den.
Advertisement
Advertisement
Millwall and West Ham have one of the most famous rivalries in English football.
And fans had high hopes that they could meet their London enemies in the Premier League next season.
Advertisement
But that dream has been snuffed out and the Blackburn supporters made sure that their opponents knew it.
Benefitting from the bonanza in Bermondsey was Sunderland, who enjoyed themselves against Preston.
Amad Diallo, on loan from Manchester United, delivered a stunning strike to set up a 3-0 win for the Black Cats at the Deepdale Stadium.
It gives them the chance to pull off a remarkable double promotion having came up from League One last season.
Advertisement
Sunderland will face Luton in the Championship play-off semi-finals next week after a season of adversity.
But Tony Mowbray, who replaced Alex Neil in August after he left for Stoke, has worked wonders with a side full of young talent.
"I'm delighted for the supporters," he said.
Advertisement
"It's an incredible scenario to see the people of Sunderland enjoying football so much, coming in their huge numbers.
"It's going to be awesome at the weekend at the Stadium of Light. We have to find another performance and we have to prepare the rest of the week and be ready for Luton."