Millwall's Wembley dream is over after a 2-1 aggregate defeat to Oxford United in the Johnstone's Paint Trophy Area Final second leg.
Lee Gregory's neat second-half goal was enough for a 1-0 victory at the Kassam Stadium on Tuesday night but a red card shown to Mark Beevers soon after proved costly as Millwall failed to score what would have been an all-important second to at least take the tie to penalties.
The first chance of the game fell to The Lions, but Steve Morison's half-volley following a knock down from Lee Gregory was blocked by Johnny Mullins on the six-yard line inside the opening two minutes.
Less than 60 seconds later the Millwall skipper again went close, this time heading Shane Ferguson's curling cross just over the bar.
Despite an even opening to the game, it wasn't until the 20th minute that Oxford made their first meaningful attack, with Joe Skarz's cross just evading the head of Danny Hylton at the far post.
Kemar Roofe, who scored Oxford's two goals in the opening leg, looked lively once again, and it was his half-volley just before the half-hour mark which gave the home side their first effort on goal.
While Jordan Archer wasn't tested on that occasion, his opposite number, Oxford keeper Benji Buchel, had to produce a smart stop straight away up the other end to deny Jed Wallace from distance. Archer was called into action moments before half-time, however, when Roofe's effort from outside the box drew a routine save from the Millwall stopper.
Millwall couldn't make the most of a glorious opportunity to go ahead on the night after 51 minutes when Gregory lifted the ball over the top for Morison, who had to wait for it to bounce before taking aim, by which time Buchel had closed the angle and was able to block.
That was to only be a temporary reprieve for the home side, however, as The Lions went in front. Aiden O'Brien received the ball in space out on the left and his cross was controlled by Gregory before the striker turned and fired past Buchel from close range after 54 minutes.
With the wind in their sails, Neil Harris' side almost made it 2-0 just moments later when Ferguson's corner made its way to Mark Beevers, who fired just over from the edge of the box.
The game was turned back in Oxford's favour after 64 minutes, though, when The Lions went down to 10 men. Moments after being shown a yellow card, Beevers had to race back to deal with Hylton, but the defender could only bring him to ground outside the box - giving referee Scott Duncan no choice but to show him a second booking.
Forced into a reshuffle, Harris replaced Shaun Cummings with Joe Martin and put the latter in Beevers' centre-half position, with Wallace having to operate as a makeshift right wing-back.
With The Lions increasingly pushing forward in search of a vital second, Oxford began to enjoy some success on the counter attack and they should have equalised 13 minutes from time when Hylton laid the ball on to Alex MacDonald, whose tame effort was comfortably saved by Archer.
Despite their numerical disadvantage, Millwall continued to throw everything they had at Oxford in the closing stages and Fred Onyedinma, on in place of Upson, should have done better with a volley after Gregory's flick-on.
Sadly that was to be the away side's final opportunity of the game, leaving Oxford celebrating their progress to April's Wembley Final.
Oxford: Buchel, Skarz, Roofe, Mullins, Wright, Sercombe, Hylton, MacDonald (Bowery, 81'), O'Dowda (Ismail, 89'), Kenny, Lundstram
Subs not used: Slocombe, Ruffels, Dunkley
Millwall: Archer, Cummings (Martin, 68'), Webster, Beevers, Ferguson, Wallace, Abdou, Upson (Onyedinma, 82'), O'Brien, Gregory, Morison
Subs not used: Forde, Thompson, Marquis
Goalscorers: Gregory 54'
Bookings: Cummings 59', Beevers 61'
Red cards: Beevers 64'
Referee: Scott Duncan
Attendance: 10,138 (1,478)