The Clarets’ dismal recent record in the Carabao Cup was extended by another shock defeat as League One Sunderland came from behind to book their place in the third round.
Sean Dyche’s men looked as though they would avoid a sixth successive exit to a lower ranked side when Jay Rodriguez put them ahead just 12 minutes in.
The summer signing first made his name as a Burnley player with some high-profile goals as the Clarets reached the semi-final of the competition in 2009.
But this time his first goal since re-joining the club turned out to be only a false dawn as Sunderland rode their luck to level before the break through Will Grigg and then deservedly completed the upset with quick-fire strikes from Tom Flanagan and George Dobson at the start of the second half.
The Clarets tested their strength in depth by making 10 changes to their starting line-up, with only teenager Dwight McNeil staying in the side that had begun Sunday’s Premier League draw at Wolves.
But this was still a side packed with quality and experience, boasting a Premier League winner in debutant Danny Drinkwater and two League Cup winners in Aaron Lennon and goalkeeper Joe Hart.
Phil Bardsley had also previously been to the final of this competition with Sunderland in 2014 and after a nip-and-tuck opening spell, the Clarets made their early superiority tell with the opening goal.
Drinkwater, making the first appearance of his loan spell from Chelsea, played his part with a typically measured pass to release Matej Vydra, who also showed great awareness to pick out the over-lapping run of Rodriguez.
The striker’s last competitive Turf Moor goal in a Burnley shirt had come in March, 2012 and he bridged the gap with a classy finish, biding his time to roll the ball past goalkeeper Lee Burge.
The Clarets, striving to improve a record of just one win in their last six games in the competition, looked to press home their advantage and 15 minutes after Rodriguez’s opening goal the Black Cats had a remarkable let-off as they somehow stayed just one goal behind.
Lennon, continuing the positive impression he has made since returning from long-term injury, smacked a shot against the foot of Burge’s right-hand post and from the rebound, Vydra hit a similar effort against the opposite upright.
Sunderland, having made eight changes of their own, almost immediately made the most of their reprieve as Dobson flicked an effort just wide from youngster Denver Hume’s dangerous ball in as they continued to look lively on the break.
And the Academy graduate again played a key role as the visitors equalised 10 minutes before half time.
This time his delivery inside was deflected off Drinkwater and fell perfectly for Northern Ireland international Grigg to stroke home his first goal of the season.
That only added to the Wearsiders’ confidence and immediately after the break they took control of the tie with two goals inside the first four minutes of the second half as Burnley's early dominance became a distant memory.
Both came from corners as the Clarets were caught napping, Hart parrying out a Lynden Gooch shot for Flanagan to nod home and then Dobson being left unattended to collect the ball on the edge of the penalty area to fire low into the bottom corner.
Burnley desperately needed a response and with an hour gone it almost came from Kevin Long who was denied twice in a matter of moments by Burge, who made fine saves to keep out headers from the Clarets’ defender.
Dyche sent on Chris Wood mid-way through the half and the striker immediately saw a shot blocked as the home side finally began to wind up a head of steam.
He then steered an effort just wide when poking the ball past the advancing Burge.
But with the Clarets unable to find a way through there was to be no nervy finish for the underdogs or a chance for Lewis Richardson to make his senior debut from the bench to become only the fourth 16-year-old to play for Burnley since the Second World War.
Burnley: Hart; Bardsley (Lowton 78), Long, Gibson, Taylor; Lennon (Wood 69), Hendrick, Drinkwater, McNeil; Vydra, Rodriguez. Substitutes: Peacock-Farrell, Pieters, Dunne, Cork, Richardson.
Sunderland: Burge; McLaughlin, Baldwin, Flanagan, Hume; Gooch, Dobson, McGeouch, Embleton; O’Nien (Power 86), Grigg (Wyke 78). Substitutes: Patterson, Ozturk, Kimpioka, Sammut, Diamond.
Referee: Darren England
Attendance: 7,445 (away 1,093)