Hibernian consigned Celtic to a third Scottish Premiership defeat of the season and prevented the champions returning to the top of the table.
Vykintas Slivka struck after just 46 seconds and Florian Kamberi finished a superb second-half counter attack with an emphatic finish.
Substitute Lewis Morgan fired narrowly wide in Celtic’s best chance.
And they finished the weekend in third place after Rangers beat Hamilton.
Brendan Rodgers’ team, however, still have a game in hand over the Ibrox side.
Hibs, meanwhile, will prepare for the second of their three home matches this week against Rangers on Wednesday.
Hibs’ intent was clear from kick-off as Emerson Hyndman and Oli Shaw moved the ball left to right for Slivka, who cut inside Jozo Simunovic to sweep a shot beyond Craig Gordon.
Slivka took a sore one after being on the end of a late lunge by Scott Brown, who was booked, and the midfielder did not reappear for the second half.
But his replacement Sean Mackie played a major role in the hosts’ second as Neil Lennon’s side broke from a Celtic corner and Mackie’s diagonal ball was collected by Kamberi and lashed past Gordon.
It could have been worse for Celtic, with Stevie Mallan’s first-half free-kick and dipping long-range drive in the second period beaten away by Gordon.
Celtic looked to James Forrest for inspiration and he twice had dangerous balls cut out with Odsonne Edouard waiting to convert a tap-in, and the winger also drew a save from Ofir Marciano.
Edouard was booked for simulation after going down in the wake of Steven Whittaker’s challenge right on the edge of the box, though replays suggested there may have been some contact.
Morgan, Jonny Hayes and Mikey Johnston were sent on to give the visitors more impetus and Morgan was inches away from halving the deficit after inventive play by Johnston.