Match ends, Livingston 2, Celtic 0.
Celtic suffered their first defeat of the Scottish Premiership season as Livingston earned their maiden win over the champions.
Second-half goals from Scott Robinson and Lyndon Dykes secured the victory against 10-man Celtic.
Ryan Christie was dismissed for the visitors midway through the first half for a foul on Robinson.
The result ended Livingston's run of four straight defeats and leaves them sixth in the table.
A Livingston masterplan
Celtic manager Neil Lennon stressed Livingston posed a "dangerous" threat before this game, and that was all too evident after just 13 minutes at the Tony Macaroni Arena.
Nicky Devlin drilled a cross in from the right and found Jon Gurthrie, who narrowly steered the shot a foot wide of Fraser Forster's left post.
Just five minutes later, a moment of ingenuity from Steven Lawless had the Livingston forward turn a set-piece outside the visitors' box into a clever one-two to get a shot away, forcing Forster to dive to his left post to keep it out.
Celtic did show flashes of promise. Odsonne Edouard almost opened the scoring moments after Lawless' chance when Christopher Jullien played his compatriot through, allowing the forward to jink to the right of his marker and sting the gloves of Matija Sarkic in goal.
However, the boisterous and physical start to the game finally got the better of the guests when Christie's attempt to intercept the ball from Robinson was far too high and showed too much of his studs for referee Willie Collum's liking and a straight red card was produced.
All eyes were on Lennon's side after the restart to see how they would respond to a disappointing first half, but it was again Livingston who claimed the initiative.
Just two minutes into the half a Livingston attack down the right found Robbie Crawford in acres of space in front of the Celtic box, which allowed the midfielder to turn and simply flick a through ball past a startled Ajer and into the path of Robinson. The 27-year old took the ball in his stride and as his marker Moritz Bauer watched helplessly from 15 yards away as the Livi man steered the ball into the net.
A startled Celtic tried to rally. A long-range free-kick from Edouard in the 53rd minute and a close-range shot from Mohamed Elyounoussi forced saves from Sarkic.
Yet, with every Celtic attack came a Livingston counter attack. Shortly after Elyounoussi's attempt on goal came a Marvin Bartley dart inside the opposing box to lay off the ball for Robinson to fire at Forster's front post. And just four minutes after a half-chance in the box for Jullien from a Celtic corner came further anguish for Lennon's side.
It was a simple punt up the park that unlocked the visiting defence, with Dykes latching on to it and lobbing Forster.
The remaining 15 minutes were perhaps the most frustrating of Celtic's league season so far as the side disputed several calls from the referee, most notably Keaghan Jacobs' needlessly rash challenge on Jonny Hayes in stoppage time that could have easily been a red.
Yet, in truth, it was a match that had looked beyond Celtic from the first minute.
Man of the match - Marvin Bartley
BBC Scotland's Brian McLaughlin at the Tony Macaroni Arena
On a day when there were a team of heroes for Livingston there is a huge difficulty in picking just one man of the match. Lyndon Dykes scored the home side's second and never gave Christopher Julien or Kristoffer Ajer a minute's piece from start to finish and was ably assisted by fellow scorer Scott Robinson.
But it was in the midfield engine room where this game was won. Hibernian fans must be wondering how they could let Marvin Bartley go on a free in the summer, and along with Keaghan Jacobs and Robbie Crawford they gave Callum McGregor and Scott Brown an afternoon to forget.
However, Bartley was the ring master for Livingston and broke up the Celtic attack time after time, and was then quick to drive his team-mates forward at every opportunity and deservedly led them to a famous victory.
- 5LamieBooked at 88mins
- 7JacobsBooked at 90mins
- 11LawlessSubstituted forOdoffinat 81'minutes
- 9DykesSubstituted forMillerat 87'minutes
- 17RobinsonBooked at 48minsSubstituted forLawsonat 76'minutes
- 2JullienBooked at 89mins
- 35AjerBooked at 90mins
- 23Bolingoli-MbomboSubstituted forHayesat 73'minutes
- 8BrownSubstituted forNtchamat 74'minutes
- 49ForrestSubstituted forBayoat 54'minutes
- 17ChristieBooked at 25mins
- William Collum
- Shots on Target
Second Half ends, Livingston 2, Celtic 0.
Attempt missed. Odsonne Edouard (Celtic) header from the centre of the box misses to the left. Assisted by Mohamed Elyounoussi with a cross following a set piece situation.
Kristoffer Ajer (Celtic) is shown the yellow card.
Keaghan Jacobs (Livingston) is shown the yellow card for a bad foul.
Jonny Hayes (Celtic) wins a free kick on the left wing.
Foul by Keaghan Jacobs (Livingston).
Corner, Celtic. Conceded by Nicky Devlin.
Attempt blocked. Odsonne Edouard (Celtic) left footed shot from the left side of the box is blocked. Assisted by Jonny Hayes.
Odsonne Edouard (Celtic) wins a free kick in the defensive half.
Foul by Robbie Crawford (Livingston).
Christopher Jullien (Celtic) is shown the yellow card.
Ricki Lamie (Livingston) is shown the yellow card.
Foul by Christopher Jullien (Celtic).
Ricki Lamie (Livingston) wins a free kick in the defensive half.
Substitution, Livingston. Lee Miller replaces Lyndon Dykes.
Foul by Vakoun Issouf Bayo (Celtic).
Lyndon Dykes (Livingston) wins a free kick in the defensive half.
Corner, Celtic. Conceded by Ricki Lamie.
Attempt blocked. Olivier Ntcham (Celtic) right footed shot from outside the box is blocked. Assisted by Callum McGregor.