Olympiacos have come from behind to record a 2-1 victory at home to Dinamo Zagreb, with both strikes coming from second-half substitute Felipe Pardo.
The opening chances of the first 20 minutes all fell to Olympiacos, as Konstantinos Fortounis shot wide before Hernani spurned two opportunities.
Zagreb made the Greek side rue their missed chances as they struck in the 21st minute through Armin Hodzic's near-post header from Josip Pivaric's cross.
Hernani played Seba through with 40 minutes played, but the Brazilian's effort was turned around the post by Dinamo keeper Eduardo.
Two former Premier League players, in the form of Brown Ideye and Patjim Kasami, combined in the opening minutes of the second half for Olympiacos but the latter's finish flew over the bar.
Ideye was then brought down in the box by Gonzalo Santos, as the Greek side were awarded a 53rd-minute penalty.
Fortounis stepped up to the spot, shooting straight at Eduardo before firing over from the rebound.
Pardo, left out of the starting XI by Marco Silva in favour of Hernani, replaced the winger after 63 minutes.
The Colombian forward's first touch of the night put Olympiacos level, as he turned Ideye's cross home for the equaliser.
Pivaric, booked in the opening half, was given a second yellow in the 79th minute after pulling down Pardo by his jersey to leave Zoran Mamic's side with 10 men for the closing stages.
Olympiacos made their numerical advantage count with Pardo recording his brace in the 90th minute, as he latched on to Fourtounis's lobbed pass before firing past Eduardo to hand his side the lead and all three points.
Marco Silva's outfit stay second in Group F, level on points with Bayern Munich and six ahead of both Dinamo Zagreb and Arsenal.