Championship side Barnsley held on to beat League One outfit MK Dons in Milton Keynes to reach the quarter-finals of the FA Cup.
Chris Dagnall fired the Tykes into the lead with a crisp finish in just the third minute and Marlon Harewood added a second from 12 yards in the 19th minute.
It was a game of two halves as Barnsley utterly dominated the opening 45 minutes before the Dons rallied following a Dean Bowditch goal just after the hour mark - racing through and placing the ball inside the near post.
The Tykes lost their composure in defence but survived waves of attack before Dagnall effectively ended the contest in the second minute of injury time, rounding David Martin to finish.
There were another 10 minutes to play after that, as earlier in the half Barnsley midfielder Kelvin Etuhu was knocked unconscious by an aerial challenge and taken to hospital. He awoke in the ambulance and hopefully he will be okay.
MK Dons did not threaten again, although Alan Smith managed to get himself sent off for a wild elbow into the side of Barnsley substitute Rory Delap.
The hosts were not at the races from kick-off, with David Flitcroft's resurgent side - who had won six and lost none of their last seven matches in all competitions, while still in the relegation zone on goal difference - pinging the ball around on a poor pitch.
Former Chelsea youth product Jacob Mellis was always a threat with balls down the channel and one such pass put in Dagnall early on. His first touch controlled the ball and took him across the defender and he picked out the bottom corner with a superb finish.
Dagnall should perhaps have scored a second from the right on 13 minutes - MK Dons full-back Jon Otsemobor playing him onside from the other side of the pitch - but blazed over.
The Dons were frustrated by the three-man Barnsley defence, which boasted extra cover in front in the form of long-term club man Bobby Hassell and the wing-backs who retreated into a compacted formation when defending.
Luke Chadwick was often forced to play with his back to goal and fellow former Manchester United man Smith barely had a sniff.
In contrast, away midfielders Mellis and David Perkins had space to attack, mostly on the counter, with Harewood and Dagnall lively in front of them.
They threatened from in behind on several occasions in the first half, but were unable to find the third goal which would have killed off the game.
Prior to the match Jason Scotland scored three goals in just 75 minutes of action for Barnsley since signing until the end of the season - all three winners in three appearances as a substitute. Again on the bench, Barnsley did not seem in need of him, but he nevertheless replaced Harewood at the break.
Karl Robinson was without key striker Izale McLeod, who was cup-tied, but sent his side out with greater purpose in the second half. Captain Dean Lewington almost headed home a corner at the near post barely a minute in and the pressure continued from there.
The match, always end to end, was also keenly contested. One such challenge on 52 minutes saw Etuhu lose consciousness after competing for the ball with home sub Adam Chicksen, delaying the match for a long period: when he was stretchered away, both sets of fans applauded him.
The goal came from nowhere, Bowditch pouncing in the centre circle to stab past Tom Kennedy and outpace him before giving Steele no chance.
With the atmosphere now generated by the home fans, MK Dons poured forward, with Irish midfielder Shaun Williams blazing a free-kick over from inches outside the box.
At the other end Perkins broke into the box to centre from the left - Dagnall was unable to divert a diving header on target after the ball was half cleared.
On 78 minutes Smith looked certain to score with a close-range header which Steele somehow turned over the bar. Five minutes further on, the keeper - a hero as Barnsley beat Liverpool at Anfield in the fifth round in 2008 then again in the quarter-finals as the Tykes beat Chelsea at Oakwell - scrambled across to tip a long-range Williams free-kick around the post. From the resulting corner, Smith sent a rising drive inches over from 12 yards.
Scotland wasted a chance on the break as holes began to appear in the attacking Dons' backline - although the shocking pitch played a part in his poor strike over the bar - but Dagnall made no mistake when sent through by Perkins in injury time.
Smith shrugged after being sent for an early bath, while his manager Robinson was furious on the touchline - Smith was unhappy with a legitimate tackle from Delap in the box moments before - but once he has seen the replays, the MK Dons boss will surely accept that it was the right decision by Mike Jones.
Barnsley's fans, buoyed by the team's recent league form, have another Cup run to shout about. After losing in the semi-finals to Cardiff five years ago, they may begin to dream again of going one better and reach a third FA Cup final, having only won the tournament once - back in 1912.
MAN OF THE MATCH
Chris Dagnall (Barnsley) - Lively in attack, his first goal was a sublime mixture of control and finish and his second coolly taken.
MK Dons: Martin 6, Otsemobor 7, MacKenzie 5, Williams 5, Lewington 6, Potter 5, Harley 5, Powell 6, Chadwick 5, Bowditch 7, Smith 4. Subs: Chicksen 6, Lines 6.
Barnsley: Steele 8, Wiseman 7, Cranie 6, Kennedy 6, Golbourne 6, Hassell 7, Perkins 7, Etuhu 6, Mellis 7, Dagnall 8, Harewood 7. Subs: Delap 6, O'Brien 6, Scotland 6.