Two second-half strikes from substitute Felipe Pardo inspired Olympiakos to a 2-1 victory over 10-man Dinamo Zagreb, sending the hosts six points clear of third-placed Arsenal in Champions League Group F.
The visitors drew first blood in the 21st minute when Armin Hodzic nodded in from the middle of the box, but after missing a penalty early in the second half, Olympiakos drew themselves level thanks to Pardo's 65th-minute strike.
Dinamo were reduced to 10 men with 11 minutes left to play when Josip Pivaric picked up his second booking of the match, and Olympiakos made the most of their man advantage, with Pardo netting in the 90th minute to seal all three points.
The game's first meaningful chance came in the seventh minute when Olympiakos midfielder Kostas Fortounis fired narrowly wide from 25 yards out.
The hosts came close once again after 15 minutes when Fortes Hernani sent his headed effort just past Dinamo shot-stopper Carvalho Eduardo's left post.
Despite early pressure from Olympiakos, it was the visitors who broke the deadlock in the 21st minute when Hodzic latched onto Pivaric's testing cross from the left wing to send a powerful header past Olympiakos goalkeeper Jimenez Roberto from seven yards out.
Olympiakos had chances to bounce back within minutes of falling behind, but headers from Dimitrios Siovas and Luka Milivojevic failed to trouble Eduardo.
The Dinamo keeper was called into action once again five minutes before the break when he parried Seba's effort from the left side of the box.
Olympiakos started the second half brightly and were awarded a penalty after 53 minutes when Santos Goncalo fouled Brown Ideye in the area, picking up a booking in the process.
Fortounis missed the opportunity to level things up from the spot, with Eduardo diving to his right to keep him out before the Greece midfielder rifled the rebound over the bar from close range.
But the hosts did not have to wait long for their equaliser, with substitute Pardo firing in with his first touch 11 minutes later. Less than two minutes after stepping off the bench, Pardo found the bottom left corner from 15 yards out after good work from Ideye.
Dinamo were down to 10 men in the 79th minute after Pivaric was shown a second yellow card for a foul on Pardo.
And Pardo earned his side all three points at the very end, rolling the ball past Eduardo and into the bottom corner of the net from the right side of the area.