PABLO HERNANDEZ dragged Leeds United back into the automatic promotion places with two goals and a man of the match display.
Millwall led twice in a hugely entertaining game but the Spaniard would not be beaten as he inspired Leeds to a vital three points.
This victory, together with Sheffield United’s shock defeat at home to Bristol City, nudged Marcelo Bielsa’s men back up to second place with seven games remaining.
It was the perfect response to the Blades’ 1-0 triumph at Elland Road a fortnight earlier, even if Leeds’ display was not up to their usual standard.
Against a Lions side who broke with pace and purpose, United missed a first half penalty when Patrick Bamford shot tamely at goalkeeper David Martin.
But it all came good thanks to Hernandez, who struck a dramatic 83rd minute winner.
Millwall had started brightly and deserved to go ahead. Jed Wallace, fresh from having an early shot blocked, spread the play to Mahlon Romeo on the right flank in the tenth minute.
He reached the ball in the nick of time, his cross picking out the unmarked Ben Thompson in the six yard box and he headed into the net.
Leeds had a golden chance to equalise eight minutes later when Wallace was adjudged to have tripped Ezgjan Alioski in the penalty area.
Referee Darren Bond pointed to the spot but Bamford’s effort was poor and David Martin saved.
Martin again rescued the Lions midway through the first half by blocking a Jack Harrison shot following an exchange of passes with Pablo Hernandez.
The Linos goalkeeper, however, could do nothing to prevent Hernandez equalising ten minutes before the break.
A sweeping move that began with some fine defending by Liam Cooper ended with the Spaniard finishing from 20 yards after a lay-off from Luke Ayling.
Millwall restored their lead ten minutes into the second half. A lightning quick break involving Romeo and Wallace that followed a misplaced pass from Barry Douglas saw the ball worked to Ben Marshall.
He cut inside Liam Cooper and was hauled down for his trouble, referee Bond again pointing to the spot. Marshall then coolly sent Peacock-Farrell the wrong way from 12 yards.
Parity was restored once again 19 minutes from time. The visitors had several chances to clear the danger but failed, allowing Douglas to cross for Luke Ayling to head in from close range.
That set up a frantic finale and Hernandez was the man who snatched all three points with a close range finish after Millwall had been opened up down their right flank.
"Pablo is a leader," said the former Argentina and Chile coach.
"He's not a leader that likes to talk a lot but he is the one who usually asks for the ball and tries to take risks that are usually hard for the players.
"Pablo is someone who gives the opportunity to change a normal attack to one where you can create a chance.
"He lifts the team and the fans too. He is someone who gives us the feeling we can hurt the opponent all the time."
Millwall played their part in a thrilling contest, twice taking the lead through Ben Thompson's header and Ben Marshall's penalty.
But Leeds have had a habit of coming from behind this term and they did so again with Hernandez scoring either side of Luke Ayling to send the home fans wild with delight.
"Some days we have to spend more time than we usually would need to spend to get what we deserve," said Bielsa, whose team also missed a penalty when Patrick Bamford fluffed his lines.
"We never feel we are going to lose. We insist on trying to change the result by keeping our style. When a team has the skill to overcome so much adversity, they deserve admiration."
The biggest cheer of the day came at full-time when Sheffield United's home defeat by Bristol City was announced, a result which leaves Leeds two points clear of the Blades.
But Bielsa insisted he is only focused on his side, stating: "Every game we play we can't be thinking about the result of any other team."
The defeat meant Millwall remain a solitary point above the relegation zone but boss Neil Harris was encouraged by the performance.
"It was probably a fair result on possession and chances created," he said.
"We were leading twice in the game and for us to come to Elland Road, it was a good performance in so many ways.
"We can talk about how good we were on the counter-attack, with the ball, how well we defended at times and stood strong at a sold-out Elland Road, but ultimately we got nothing from the game.
"Leeds are a top side and we ran them very close today."