Murray Wallace scored a dramatic 94th-minute winner to earn Millwall a famous FA Cup fourth-round win over Everton at The Den.
Everton led when keeper Jordan Archer failed to hold Richarlison’s strike before Lee Gregory’s looping header levelled the scores.
Cenk Tosun restored the visitors’ lead only for Jake Cooper to equalise with a controversial goal off his arm.
Wallace slotted the winner after Shaun Hutchinson’s downward header.
There were wild scenes at the final whistle as jubilant Lions boss Neil Harris joined his players on the pitch and Millwall’s fans gave their battling team a standing ovation.
The second-tier club might have needed a moment of fortune to equalise a second time but they showed tremendous character after twice falling behind to make Monday’s fifth-round draw.
Everton, without a major trophy since 1995, will feel aggrieved Millwall’s second equaliser was allowed to stand.
The visitors were furious after Cooper used his arm to nudge the ball over the line.
However, with no video assistant referee (VAR) in operation, referee Michael Oliver allowed it after consulting one of his assistants.
Ironically, VAR is used at all Premier League grounds in the FA Cup and Cooper’s goal would almost certainly have been ruled out if the tie had been at Goodison Park.
Elsewhere West Ham manager Manuel Pellegrini said his side’s defeat by AFC Wimbledon was a “disaster” as the League One side pulled off a stunning FA Cup shock to reach the fifth round.
The Dons, bottom of the third tier of English football, surged into a 3-0 lead against the Premier League side courtesy of Kwesi Appiah’s deflected strike and Scott Wagstaff’s double either side of half-time.
Pellegrini made a triple substitution at the break in an attempt to get back into the game and saw two of his changes – Lucas Perez and Felipe Anderson – score to make it 3-2.
But AFC Wimbledon, who were beaten 3-0 at home by Fleetwood in their last league game on Tuesday, continued to push men forward and put the seal on a famous victory courtesy of Toby Sibbick’s late close-range header, sparking scenes of jubilation among the home crowd and leaving Pellegrini furious.
“Was I angry at half-time? Yes of course – I was ashamed of them,” said Pellegrini.
“It’s very easy to explain what happened – it was one team who wanted to win and another team who played without any desire or any ambition to win or continue in this cup.
“Maybe we thought we were going to win because we are a Premier League team and they are in League One, but Wimbledon played with the desire to compete in this cup. In the first 45 minutes, we didn’t fight.
“It’s very frustrating because you can be eliminated, but not in the way we were. It’s a disaster.”
And at Etihad, Burnley manager Sean Dyche suggested Manchester City could “win everything” this season after the Premier League champions thrashed his Clarets side 5-0 to reach the FA Cup fifth round.
Goals from Gabriel Jesus, Bernardo Silva, Kevin de Bruyne, an own goal from Burnley’s Kevin Long and Sergio Aguero’s penalty gave City an easy win.
“They have elite players and are so clinical,” said Dyche.
“Who is going to stop them winning everything if they’re in that mood?”
Dyche, whose side lost for the first time in six matches, added: “It is very difficult when teams like this play the way they do.
“They are a top, top team and if you catch them on a day like today they punish every mistake you make.”
Pep Guardiola’s team won the Premier League and Carabao Cup last season and are still on course for a quadruple in 2018-19.