League One side Mansfield Town came from behind to beat Premier League strugglers Burnley and reach the fifth round of the FA Cup for the first time since 1975.
Josh Laurent gave the Clarets the lead midway through the first half but goals from Rhys Oates and Louis Reed completed a brilliant second-half turnaround to help the Stags progress.
Veteran Burnley forward Ashley Barnes had a glorious opportunity to open the scoring early on, when he slid in to connect with Quilindschy Hartman's cross but somehow diverted wide from just a few yards out.
The Premier League side deservedly went in front after 20 minutes through Laurent who showed brilliant composure inside the area, feinting to shoot and putting Mansfield goalkeeper Liam Roberts on the ground before slotting into an empty net.
Jacob Bruun Larsen, who is still yet to score for Burnley since his summer move from Stuttgart, was inches away from breaking his duck when he burst through on goal and dinked over the onrushing Roberts, only to be denied by an excellent goalline clearance from Kyle Knoyle.
Mansfield thought they had found a leveller before the break when Oates broke the offside trap before finishing brilliantly past Max Weiss, but he was penalised for a foul on Hjalmar Ekdal in the build-up.
The visitors came out of the traps fast in the second half and really should have been level when Oates found himself in a one-on-one after a slip from Ekdal but with just Weiss to beat he put it well over the bar.
But Oates got a second chance to tie things up and this time took his opportunity, climbing above his man to head home brilliantly from a Knoyle cross.
Burnley took control of the game again soon after but it was the League One side that turned the game on its head when captain Reed curled in a delightful free-kick from 25 yards with just 10 minutes remaining.
Zian Flemming could have salvaged the game for Scott Parker's side when he blazed over from six-yards out in stoppage time but the Stags held on to complete a memorable upset.
Parker made nine changes to the side that produced a brilliant comeback away at Crystal Palace in the league in midweek - and the weakened team ultimately came back to bite the Clarets.
Bruun Larsen, Barnes and Loum Tchaouna all missed gilt-edged chances to put the game beyond Mansfield on the day but their lack of game-time showed with rustiness in front of goal.
Parker's side finished with an expected goals tally of 3.82, their highest of the 2025-26 campaign by some distance - yet they were only able to find the net once.
Had any of the chances fallen to the likes of Jaidon Anthony or Flemming, you would have fancied they would have taken them.
It begs the question why exactly Parker made so many changes to a side that do not play again for seven days.
A League One opponent arguably provided the perfect opportunity to build momentum and claim two successive wins for just the third time this season.
After such a morale-boosting victory against Palace, the Clarets have been brought back down to earth with a large bump.
With no cup competitions left to take part in and survival chances looking increasingly slim, it looks like it may well be another season to forget.