Celtic have left themselves with it all to do to reach the Champions League after a surprise 2-0 defeat to Kazakhstan champions Shakhter Karagandy in the first leg of their play-off at the Astana Arena.
Having started the game well, Celtic found themselves behind in the 12th minute when Andrei Finonchenko took advantage of some slack defending to score from close range.
Kris Commons rattled the bar with a thunderous drive in the 19th minute with the ball bouncing down on to the line but Celtic struggled at times with the route-one approach taken by a home side who looked limited in other aspects of their game.
Celtic had the best of things again in the second half with James Forrest missing a chance from six yards. But in the 77th minute Sergei Khizhnichenko headed in a second to leave shell-shocked Celtic having to make amends in next week's second leg in Glasgow.
Neil Lennon, though, will be puzzled as to how Celtic have work to do against a basic team who themselves may wonder how they managed to emerge from the tie with a win.
Two of Celtic's summer signings, Virgil van Dijk and Steven Mouyokolo, made their European debuts and started in central defence together for the first time as Efe Ambrose dropped to the bench.
Mikael Lustig replaced Adam Matthews at full-back, the defender recovering from a hamstring injury but only finding a place as substitute as Forrest came in for Beram Kayal.
Shakhter, the first Kazakh side to reach the play-off round of the competition, were playing 114 miles away from home in the 30,000-capacity national stadium, which was close to full with a couple of dozen Celtic fans in one corner behind a goal.
Celtic dominated the early stages on the artificial surface and indeed could have been two ahead before they fell behind. Shakhter escaped in the fourth minute after keeper Aleksandr Mokin fumbled a Charlie Mulgrew corner and Van Dijk and Commons tried to get the ball in but it was scrambled away for another corner.
When Commons flighted the ball into the box from the other side, Van Dijk powered a header in which was parried by Mokin and Shakhter somehow survived again.
Shakhter were probably as surprised as anyone when they forced their way into the lead with what was a basic goal. A long throw-in from the left by midfielder Gediminas Vicius was headed on by Nikola Vasiljevic and Finonchenko stole past Joe Ledley to knock the ball past Fraser Forster from close range.
The home fans could not believe their luck and they cheered every attack in the moments following but Celtic stabilised and when Commons hit the woodwork it reminded them their side remained under threat.
In the 29th minute, just after Shakhter defender Sergei Maliy had headed a cross from Aleksandar Simcevic over the bar from 14 yards, Georgios Samaras skimmed a header from a whipped-in Mulgrew free-kick just inches past the far post.
Celtic had another opportunity four minutes from the break when Van Dijk got on the end of a Mulgrew corner but his header was directed straight at Mokin.
Celtic came out for the second half with some purpose and set about getting themselves level. Emilio Izaguirre should have netted in the 51st minute after taking a Commons pass and burrowing his way into the box but he slashed at his shot which flew over the bar.
Shakhter were defending in numbers and relying on the occasional break for respite. One break ended with Khizhnichenko getting a shot away which lacked the power to really test Forster but which brought thunderous cheers from the home fans, by now sensing a famous victory.
Celtic continued to press and in the 72nd minute Forrest had a glorious chance when Izaguirre planted a cross on his head six yards from goal but his effort was straight at Mokin who gratefully blocked to safety.
The closing stages were frantic but again Celtic were slack when conceding the second. Mouyokolo did well to block a goal-bound shot from Khizhnichenko but when the ball was crossed back in to the box by Vicius he steered a header past Forster from 10 yards.
Celtic were stunned and the final minutes passed in something of a blur for the visitors with Mulgrew heading over from six yards in the final minute.
After getting past Cliftonville and Elfsborg in the previous two qualifiers, Celtic now need to pull something special out of the bag next week, although in front of their own fans that is far from unlikely.