Maribor - Chelsea were left waiting for their place in the last 16 of the Champions League after coming from behind to draw 1-1 away to Maribor on Wednesday.
Jose Mourinho's side then squandered a gilt-edged chance of victory after the Slovenian side had threatened to pull off the shock result of this season's competition.
Premier League leaders Chelsea, who only a fortnight earlier thrashed Maribor 6-0 at Stamford Bridge, fell behind to Agim Ibraimi's 50th-minute goal in this Group G clash.
The hosts should have gone 2-0 up but Luka Zahovic somehow contrived to miss an open goal as the game entered its final 20 minutes and were made to pay as Nemanja Matic equalised to spare the blushes of Mourinho's team.
Chelsea then missed several chances before Eden Hazard won a penalty with five minutes remaining after being brought down in the box by Mitja Viler.
Hazard took the penalty himself but impressive goalkeeper Jasmin Handanovic dived to his left to save the spot-kick.
Ibraimi's curling shot from the edge of the box had given Maribor the lead but Matic drew Chelsea level when he struck from close range afer good work by John Terry following a corner.
Chelsea could have won the match late on but Handanovic made excellent saves to deny both Hazard and Diego Costa.
But in an open game, Maribor had their chances to seal what would have been a stunning win, with striker Marcos Tavares shooting wastefully wide from the edge of the box with 10 minutes left.
Then came the penalty chance and, on a night of surprises, none was greater than Hazard's failure to make it 2-1.
Had Chelsea -- the 2012 Champions League winners -- beaten Maribor and other results gone their way, they would have qualified for the last 16 of this season's competition with two games to spare.
It was not the result Chelsea would have wanted ahead of their Premier League clash with Liverpool on Sunday.
In the build-up to this match, Mourinho had been at pains to label Chelsea's 6-0 home win a "fake situation", saying he knew Maribor were a "good team".
Kurt Zouma could have given the visitors the lead but headed wide from a Cesc Fabregas corner.
But Chelsea failed to get going in the first half and Mourinho responded by sending on Costa and Oscar after the break in place of Willian and Schurrle.
However, five minutes into the second period the visitors were behind after Chelsea, failing to clear the ball properly, saw Ibraimi beat Cech with a superb curling shot into the far corner.
Ramires replaced Filipe Luis as Mourinho switched to three at the back.
But as Chelsea were adjusting to their new defensive formation, Viler sped forward and crossed to the back post, where Luka Zahovic shot over the top when it seemed easier to score.
Oscar's deflected shot led to Chelsea's equaliser from the ensuing Fabregas corner, with Terry heading the ball down for Matic to lash home.
Hazard should have made it 2-1 but was denied by Handanovic when one-on-one with the goalkeeper, who later tipped Costa's volley over the crossbar.
Costa did put the ball in the back of the net but his effort was disallowed for offside.