Hibernian put a dent in Celtic's Ladbrokes Premiership aspirations with a shock 2-0 win over the Hoops at Easter Road.
Midfielder Vykintas Slivka got the home side off to a dream start when he finished off a fine move with just 46 seconds played and in the 59th minute striker Florian Kamberi hammered in a clinching second
It was Celtic's first league defeat in 10 matches and they remain one point behind Kilmarnock albeit with two games in hand and with Rangers able to leapfrog both against Hamilton later on Sunday.
Rejuvenated Hibs won for the first time in eight games last week against Hamilton and will see this victory as confirmation of a return to early-season form.
However, it has been a mixed few days for Brendan Rodgers' side who qualified for the last-32 of the Europa League on Thursday night despite a 2-1 defeat at Parkhead by Salzburg.
They had no time to settle into the game as the returning Steven Whittaker and Emerson Hyndman combined for a stunning opener.
A sweeping move started with Whittaker brilliantly working himself out of the right-back position before feeding Hyndman, who moved it on to Oli Shaw.
When he switched the ball back to the right-hand side Slivka controlled it on his right foot, moved it on to his left past Parkhead defender Jozo Simunovic and then curled it past Hoops keeper Craig Gordon into the far corner.
Then, in the 12th minute, Gordon made a decent save from Stevie Mallan's 25-yard free-kick, after Emilio Izaguirre had clattered into Whittaker.
The visitors were off the pace although French striker Odsonne Edouard curled an effort from outside the Hibs box just over the bar.
Hibees keeper Ofir Marciano had to claw away a Sinclair chip at the start of the second half for a corner which came to nothing before a great cross at the other end from Mackie missed a couple of Hibs shirts by inches.
Play became increasingly stretched.
Marciano saved a James Forrest drive but as Celtic mounted another attack, they suffered when it broke down and Hibs countered.
With Celtic's defence posted missing, Mackie's long diagonal pass found Kamberi running past Brown and the Hibees attacker sped into the box before thrashing the ball high past Gordon to stun the champions.
Moments later Kamberi's cross just missed DAryl Horgan at the back post and then Rodgers made a double substitution, Scott Sinclair and Izaguirre making way for Lewis Morgan and Jonny Hayes.
As Celtic pressed to get back into the game, Edouard was shown a yellow card by referee Don Robertson for simulation inside the Hibs penalty area.
The Hoops striker soon made way for Mikey Johnston, who moments later slid a pass across the Hibs six-yard box but found no takers.
Celtic kept pushing and Morgan's left-footed drive from 12 yards escaped the far post.
In the 81st minute, at the other end, Gordon palmed away a Mallan shot but Celtic stormed back in the final stages, only to find the Easter Road defence rock solid.