Kostas Mitroglou scored an injury-time winner as Olympiakos snatched the three points in Montpellier.
Mitroglou nets late winner for Olympiakos against Montpellier
Substitute Kostas Mitroglou scored an injury-time winner as Olympiakos stunned French champions Montpellier.
The Greek side had just two shots on target all night, but after skipper Vasilis Torosidis scored his first goal in over two years, Mitroglou tapped home the winner in added time.
It was rough justice on Montpellier, who had deservedly led through Gaetan Charbonnier's clinical finish just after half-time.
But their failure to convert a host of chances was cruelly punished to leave them bottom of Group B with just a single point.
Olympiakos had lost their opening two matches and looked second best for a large part of the opening period.
Montpellier boss Rene Girard, who was serving a touchline ban, cut a frustrated figure in the stands as his side missed a host of chances.
But the hosts' early pressure began to fizzle out as the Greek side settled.
Benjamin Stambouli had to block a Rafik Djebbour header at close quarters before the striker just failed to get a foot on Leandro Greco's dangerous cross from the left.
Greco caused more problems down his flank but Paulo Machado wasted the chance.
Eventually the hosts did take the lead just three minutes after half-time thanks to some quick thinking from Charbonnier.
The striker initially flicked a header forward, and when the defence was only able to poke the ball back into his path, he lashed his shot in from just inside the area.
Olympiakos passed up a glorious chance to draw level moments later when Pablo Contreras floated a cross to an unmarked David Fuster at the back post but he headed wide.
Montpellier then should have killed off the game but passed up a series of chances.
John Utaka forced Carroll into a save before Belhanda missed their best opening. The striker latched on to another weak clearance but after feigning by a defender he arced his shot wide.
Costly
It proved costly as Olympiakos drew level on 73 minutes when Jose Holebas whipped a set-piece into the six-yard box where skipper Torosidis was able to take a touch before volleying home.
Montpellier pressed forward in search of a winner they just about deserved, but were instead caught on the counter-attack.
After losing the ball on halfway the French side still had a chance to clear the threat, but Henri Bedimo was caught on the ball and Djamel Abdoun raced clear and centred for Mitroglou to tap in.
