MILLWALL finally got their first away win this season, in their 4,000th game in the Football League, and none of the previous 3,999 could have been as absorbing or bonkers as this 4-3 victory at Elland Road.
The Lions roared into a 2-0 lead, Leeds United also down to 10 men at half-time after Liam Cooper's red card for a late tackle on George Saville.
But Leeds stunned the visitors with three goals to go 3-2 up, a lead they held until the 87th minute.
Millwall could have been out of sight by the break as Aiden O'Brien put his side in front with his fourth goal in three games when he headed in Steve Morison's cross.
Shaun Hutchinson hit the woodwork before Cooper was sent off in the 38th minute, after Lions assistant boss Dave Livermore and Leeds coach Paul Butler had been sent to the stands following the defender's tackle on Saville.
Lee Gregory made it 2-0 two minutes before half-time, Morison enjoying his afternoon with another assist against his former club.
But the home side turned the game completely on its head in the first 17 minutes of the second half. Pierre-Michel Lasogga pulled a goal back before Kemar Roofe scrambled home from close range in the 55th minute after Jordan Archer's mistake.
And Millwall were in disbelief when Lasogga took aim from 25 yards to fire past Archer into the bottom left corner.
It got worse when O'Brien had to go off injured, with Shane Ferguson came on for him in the 63rd minute. Three minutes later Harris sent on Tom Elliott for James Meredith with his side now trying to find a way back into the contest.
The game seem to have slipped away from Millwall, but there was still more to come on a ridiculous day of drama.
Elliott – who came through the youth system at Leeds – equalised three minutes from time, before Jed Wallace darted forward to fire home the winner via a deflection.
It was Millwall's first away in the Championship since February 2015, and Harris paid tribute to Leeds for the way they fought back to be on the verge of claiming an unlikely win.
"First of all, well done to Leeds. As disappointed as I was with our game management, they were good," Harris said.
"Barring the first five minutes, eleven v eleven we were excellent first half.
"Away at Elland Road I told the players [at half-time] the game wasn't done, you have to kill the game. Their players were always going to have a spell and the fans were always going to get behind them.
"It's how you bounce back and we completely lost composure for 15 minutes. We made really poor decisions with the ball.
"So I was pleased with the character we showed at the end."
It was Millwall's first win away from home this season at the 14th time of asking, and the first time Harris has experienced a Championship win as a manager on the road in 19 games.
Harris picked forward-thinking side and was rewarded with two first-half goals from a vibrant attack.
The Lions had 26 shots on goal, but looked like they had blown it after that sloppy spell after half-time.
"It's a big one for us. It looked like a banker of a home win," Harris said after seeing his side trail in the closing stages. "That first half was how we played at Villa, Brentford, etc."
"Out of nothing they [Leeds] can score goals so I thought we needed an attacking team. I felt we needed to score."
Archer someway made up for his earlier error when he saved from Conor Shaughnessy from close range in the 93rd minute, before referee David Coote finally called a halt to the madness three minutes later, to leave a small pocket of the Elland Road crowd of 33,564 in raptures.
"The fans for both sides were fantastic," Harris said. "The players for both sides fed off that in the game."
Image: Millwall FC