Joe Martin hit a stunning free-kick to crown a superb team display and put Millwall firmly in the driving seat of their League One Semi-Final against Bradford City.
The Lions were rocked when Tony McMahon fired the home side ahead on 13 minutes in Sunday's first leg at the Coral Windows Stadium, but responded in perfect fashion as Lee Gregory bagged his 26th goal of the campaign to level just 60 seconds later.
Steve Morison took his season's tally to 19 with a textbook header nine minutes before the break and Martin crowned a near perfect first-half display with a sublime 25-yard free-kick to hand Neil Harris' men a crucial two-goal cushion ahead of Friday's second leg at The Den.
Manager Harris made two changes to his starting XI, with top scorer Gregory back in the starting line-up at the expense of Aiden O'Brien, who took his place on the bench whilst Carlos Edwards slotted in seamlessly at right-back in place of the suspended Mahlon Romeo.
Both sets of fans were in fine voice long before the game started with around 2,000 Lions supporters certainly holding their own in the volume stakes.
Bradford started strongly, so much so that their physical approach earned The Lions a handful of free-kicks in the opening exchanges of an absorbing encounter.
However it was the home side who were handed a golden opportunity to break the deadlock on 13 minutes when Martin was penalised for a foul on the edge of the penalty area.
McMahon's resulting free-kick was headed back across goal by Jamie Proctor, hit the hand of the unfortunate Martin and referee Whitestone pointed straight to the spot.
However McMahon could count himself extraordinarily lucky to even be in a position to step up and take the penalty, having only been shown a yellow card for raising his hands to the face of Chris Taylor seconds before converting the spot-kick.
Millwall's indignance quickly turned to elation as Harris' men conjured an equaliser less than 60 seconds after going behind.
Skipper Morison knocked Martin's long ball down the left into the path of Gregory, who in turn showed the predatory instincts that have served him so well this season, swivelling on a six pence and firing past keeper Ben Williams.
It could have been 2-1 to Millwall moments later when Morison despatched an inviting cross that was met by the head of Taylor, but his effort went straight into the keeper's hands.
A neat one-two between Gregory and Morison saw the latter fire over just before the half-hour mark but The Lions did finally make their pressure count five minutes later when Morison's bullet header from Shane Ferguson's corner left Williams rooted to the spot.
It took a stupendous block from midfield dynamo Ben Thompson to block a drive from Evans as the home side searched for an equaliser, but it was Millwall who were in dreamland as the opening half drew to a close.
Gregory was sent to ground - not for the first time either - around 25 yards out on the right of the penalty area. Left-back Martin measured his free-kick to perfection, curling a sumptuous effort into the top corner.
A superb first-half so nearly produced a fourth goal in injury-time when Gregory's spectacular scissor-kick from Taylor's inch perfect delivery flew off target.
As first 45 minutes go, it was near perfect from Millwall and the big question was whether they would be able to withstand what was to follow from the shell-shocked Bantams.
It took brilliant tackles from Thompson and then Taylor in quick succession to break up promising Bradford attacks as the home side started the second period like men possessed.
McMahon, booked in the first half, could count himself fortuitous that he was still on the pitch after a late challenge that sent Ferguson flying.
Bradford remained relentless in their pursuit of reducing the deficit and the Millwall goal certainly led a charmed life when Proctor somehow kept the ball in play and squared to former Lion Filipe Morais who screwed his shot horribly wide of an open goal.
The Lions introduced O'Brien and then Tony Craig as the game entered the final half an hour and Bradford's pressure cranked up a notch.
Jordan Archer was called into action with an acrobatic tip-over to keep out Clarke's powerful header and the keeper then bravely collected at the feet of Davies as the home side kept their foot on the gas.
However whatever Bradford threw at Millwall, The Lions dealt with supremely as a unit and could even have added further goals on the counter with Morison twice hitting first-time shots that dipped narrowly over.
It was imperative that Harris' men kept a clean sheet in the second-half and the character, resilience and effort shown by the players was top notch.
Huge credit to should go to the 1,828 supporters who got right behind the team from the start and found their voices once again in the five minutes of injury-time to see Millwall over the line for a thoroughly deserved victory.
Now it's a case of finishing the job on Friday night at The Den as there is still plenty of hard work ahead.
Williams, Darby, Meredith, Evans, Clarke, Cullen, Reid, Proctor, Morais (Davies, 69mins), McArdle, McMahon (Anderson, 82mins). Subs not used: Cracknell, Morris, Leigh, Routis, Thorpe.
McMahon (13mins, pen)
Archer, Edwards, Martin (Craig, 71mins), Beevers, Webster, Abdou, Thompson, Ferguson (Williams, 89mins), Gregory (O'Brien, 64mins), Morison, Taylor. Subs not used: Forde, Nelson, Upson, Onyedinma.
Gregory (14mins), Morison (34mins), Martin (44mins)
19,241 (away 1,828)