Hibs hopes of creating a club record of winning their first six league matches of the season were crushed as Ayr United came from behind to inflict a first Championship defeat on Neil Lennon's players
It was looking oh so good for the Capital outfit after Jason Cummings had given them a deserved lead with his eighth goal of the season but it all went horribly wrong after Easter Road midfielder Marvin Bartley was sent off 23 minutes from time.
Ayr made the most of their numerical superiority, former Hearts defender Conrad Balatoni powering home a header before Brian Gilmour completed a stunning comeback for Ian McCall's side, sliding home the winner from six yards out to knock Hibs off the top of the table.
Hibs almost got off to a dream start, Grant Holt meeting David Gray's cross with a powerful downward header that thumped off Ayr goalkeeper Greg Fleming before spiralling up oiver his bar.
The Easter Road outfit totally dominated the opening half-hour without being able to find a way through although Fleming had to go down at the feet of Lewis Stevenson to prevent him cashing in on Balatoni's failure to deal with Jason Cummings' flick.
Hibs would have headed up the tunnel at half-time bemused to still be on level terms such was the possession they'd enjoyed but, having said that, other than that early Holt header they hadn't caused Fleming any real difficulties.
But it took the Capital club only five minutes of the second half to get the goal they probably felt they deserved, and what a beauty it was, Cummings picking up the ball 25 yards out and with only one thing on his mind. And he left Fleming helpless with a glorious, curling left foot shot high into the top corner of the net.
Ayr, though almost stunned Hibs, Jamie Adams getting up to meet Gilmour's corner only to see his header taken off the line by Fraser Fyvie.
Hibs, however, were reduced to ten men when Bartley was controversially sent off in the 67th minute, referee Nick Walsh deeming his challenge on Adams was worthy of a red card - much to the fury of the home fans.
And Ayr cashed in on Bartley's dismissal, Balatoni coming in unopposed to meet Gilmour's corner to power a header into the net for what had appeared to be an unlikely equaliser.
Worse was to come for Hibs as Ayr got a second ten minutes from time, Kevin Nisbet's run and cutback met by Gilmour who had the easy task of sliding the ball into the net from six yards out.
Hibs: Marciano, Gray, McGregor, Hanlon, Stevenson, Bartley, Fyvie, McGinn, Shinnie (Keatings 83), Cummings (M Boyle 78), Holt (Graham 59)
Substitutes not used: Laidlaw, McGeouch, Forster, Harris.
Ayr United: Fleming, Devlin, Balatoni, Meggatt, P Boyle, Gilmour, Adams, Docherty, Cairney (Nisbet 55), Harkins (McGuffie 65), Forrest.
Substitutes not used: Hart, Murphy, Thomas, Crawford, Donald.
Referee: Nick Walsh