Roy Carroll and David Fuster were Olympiacos' heroes as the Greek champions took a significant step towards the last 16 of the Europa League with a 1-0 first-leg victory over Rubin Kazan in Moscow.
Fuster netted the only goal of the game in the 72nd minute but veteran goalkeeper Carroll, on his debut, also played a key part in the win by saving a penalty from Bebras Natcho with his first touch after coming on in the 73rd minute.
The 34-year-old Carroll, who only joined the club last month, was called into action after first-choice goalkeeper Balazs Megyeri had been shown a red card in conceding the spot-kick with a foul on Gokdeniz Karadeniz.
The 10 men of Olympiacos then held out for the final 17 minutes at the Luzhniki Stadion to record a victory which put them in pole position to progress to the next phase.
In the day's other game Sporting Braga's hopes of repeating last year's run to the final were hanging by a thread after goals from Tomas Sivok and Simao gave Besiktas a 2-0 victory in the first leg in Portugal.
Helder Barbosa's first half sending-off for two bookable offences hindered the home side, who must now pull off an extraordinary recovery in the second leg in Turkey in order to book their place in the last 16.