Remarkable Livingston piled yet more misery on Celtic to push under-fire manager Neil Lennon closer to the brink.
A second string Lions line-up held the 10-man Parkhead side to a second draw in just four days at a snow covered Tony Macaroni to leave them still without a win in 2021.
Ciaron Brown nodded the hosts into an early lead before goals from Mohamed Elyounoussi and Nir Bitton put the champions on course for a badly needed victory.
But Jay Emmanuel-Thomas levelled in the second half before Celtic captain Scott Brown was sent off just minutes after coming on as a sub.
A 2-2 draw means Lennon's side have squandered one of their three games in hand in a bid to hunt down runaway leaders Rangers.
And the result piles yet more pressure on Lennon as this disastrous tilt at 10 In A Row goes from bad to worse.
David Martindale admitted ahead of kick-off he had one eye placed firmly on Sunday's Betfred Cup semi-final against St Mirren and that was reflected in a team selection that made the result all the more impressive.
He rung seven changes from the weekend draw in Glasgow, resting key men Scott Robinson, Josh Mullin and Craig Sibbald.
Lennon, meanwhile, brought back the bulk of his top stars who'd joined him in quarantine over the past 10 days.
But was a familiar tale of set-piece woe that left Celtic trailing.
Just as against Hibs, a silly foul in midfield allowed Livi to float the ball into the box and Brown was allowed to wander freely into the box and head past Vasilis Barkas.
It was the wake-up call the sluggish visitors seemingly needed as they emerged from their collective shell in search of an equaliser.
Shane Duffy had a close-range header blocked but from the resulting corner, the equaliser arrived in stunning fashion.
Leigh Griffiths' whipped in-swinger found Elyounoussi darting across his man and he steered an exquisite volley in off the crossbar.
Livingston's early adventure had now been significantly curtailed as the visitors upped the tempo in search of a second, penning their hosts into their own box for long spells.
Their attempt to rush out on Callum McGregor as he feigned to pull the trigger left Bitton standing all alone but in an suspiciously offiside position and the midfielder slipped in his team-mate to fire in off the advancing Robbie McCrorie.
The hosts were being run ragged and but for the on-loan Rangers keeper would have conceded a third on the cusp of half-time.
David Turnbull swept forward with menace on the counter-attack and his deft through ball ran into the path of a galloping Ajer - but his attempt to slot was blocked by the keeper.
Celtic remained dominant after the restart but their tendency for self-destruction is never far off these days and so it proved again.
Brown surged forward down the Celtic right and his low cross found Emmanuel-Thomas outrunning Greg Taylor to slot home a very tidy equaliser.
It set up a momentous last 20 minutes as conditions worsened under heavy East Lothian snowfall.
By the time we reached the final stages, the lines on the pitch were barely visible and a somewhat farcical element took over proceedings as players slipped and slid all over the plastic surface.
That was only compounded by Brown being shown a straight red due to a flailing arm just five minutes after entering proceedings.
It ended Celtic's chances of sneaking a win and surely with it their title aspirations.
Livi keep defying the odds
The 10 In A Row saga will take the headlines but Livingston are fast becoming arguably the story of the season.
Even when Martindale sacrificed his key players in a bid to stay fresh for Sunday's last four showdown, they still manage to grind out a result against the toiling champions.
This was a stark contrast to their weekend draw at Parkhead, from which Livi left Glasgow disappointed not to take all three points.
They were made to suffer for spells here but their resilience and, make no mistake, quality helped them dig out a point and keep their remarkable unbeaten run going.
Brown's moment of madness
The captain was thrown on in the closing stages to galvanise his struggling team-mates but his cameo was shortlived.
The midfielder was found guilty of throwing an arm at Kabia and promptly sent off by referee Willie Collum.
It was a quite dreadful conclusion to another quite dreadful evening for the defending champions.
Barring a miracle, their 10 In A Row dream surely disappeared down the tunnel with their dismissed captain.
Lennon on the brink
The Celtic manager's explosive Monday press conference reignited a fire under their ill-fated Dubai trip just as it felt it had begun to peter out.
It made a win even more important for a side who could already ill-afford any further slip ups with Rangers so far off in the distance.
Celtic looked to be heading for a comfortable win when the teams departed for the interval but yet more defensive lapses cost them dearly again.
It could well prove fatal for Lennon.
