Manchester City midfielder Phil Foden finished off a brilliant team move as his side saw off Olympiakos 1-0 away from home on Wednesday to book its place in the Champions League's last 16.
After dominating possession with little reward, City found a breakthrough in the 36th minute when Gabriel Jesus trapped a crossfield ball and fed Raheem Sterling, who produced a sublime backheel pass for Foden to slam the ball into the net.
The Greek side stayed in the game and was not far from finding a late equalizer when Kostas Fortounis pulled his shot just wide of the far post from a tight angle, while defender Pape Cisse headed over the bar in added time.
City's fourth consecutive win in Europe's elite competition left it top of Group C with 12 points, while Olympiakos is third with three.
After failing to take its chances against Tottenham, City again lacked ruthlessness in front of goal against Olympiakos and should have built on its lead.
Sterling saw a thumping free kick tipped over the bar by Olympiakos keeper Jose Sa, who also thwarted Joao Cancelo after the break, while Bernardo Silva and Foden missed the target from clear openings.
Olympiakos nearly made them pay with its late chances but City saw the game out to make the knockouts for the eighth consecutive campaign.
"Fair play to them, they came out fighting in the second half and made it hard for us," said match-winner Foden.