BURNLEY'S promotion party has been put on hold, after suffering back-to-back home defeats for the first time in over two years.
The Clarets went into the game knowing that a win for them and anything but a win for Derby County would secure their place in the Premier League.
But despite bossing both halves, and creating a host of chances, Burnley - beaten last time at Turf Moor by leaders Leicester City - could not find the back of the net.
Instead, Middlesbrough broke from a Clarets corner and scored through Jacob Butterfield.
It was enough to make Middlesbrough the only team to do the double over Sean Dyche's side this season, despite ending the game with 10 men after Daniel Ayala's late sending off.
It also reduced the gap to second place to eight points, after Derby County came back from behind to beat nine-man Huddersfield Town 3-1.
But Burnley will be mystified as to how they did not manage at least an equaliser.
Practically all of their 10 outfield players had chances to score, with goalkeeper Tom Heaton even going up for a late corner.
Danny Ings sent an early volley over from the fit-again Kieran Trippier's brilliant ball, Michael Kightly then saw a header bounce off the bar, with Ashley Barnes nodding over the rebound.
Ings stung Dimi Konstantopoulos' hands in between a couple of Boro chances, before Burnley were required to scramble a corner clear after Danny Graham's shot was saved by Heaton, who went on to tip over from Jacob Butterfield in a goalless first half.
Gary Parkinson, a favourite of both clubs, made an emotional Turf Moor return with his family as the Clarets' guest of honour, coming out to a terrific reception at half-time, accompanied by his old team-mate and fellow Wembley play-off hero David Eyres.
It was his boyhood team who took the lead through Butterfield on the break six minutes into the second half.
The Clarets had started on the front foot, but after failing to capitalise on a corner they allowed Boro to counter and Butterfield finished the move emphatically.
Lee Tomlin bent Another chance wide, but after that there was a succession of chances for Burnley, not to mention a host of failed penalty appeals.
Jason Shackell had a header cleared off the line, Barnes' header was tipped away, Trippier had a free kick destined for the top corner saved, David Jones had a free kick tipped over, substitute Ross Wallace brought a good save from Konstantopoulos, Michael Duff had a shot from a corner blocked behind and Ben Mee glanced a header from the follow-up flag kick wide.
Try as they might it would just not go in.
The promotion push rolls on to the Good Friday game at Blackpool.