A humiliating 5-1 defeat at Eintracht Frankfurt on Sunday (AEDT) brought an end to Kovac's 16-month tenure and caretaker boss Hansi Flick saw his side frustrated for large parts by Jose Sa.

The visiting goalkeeper made several sharp stops and Benjamin Pavard hit the post, but Lewandowski's sixth goal of the group stage broke the away side's resolve.

Substitute Perisic made sure of the points late on meaning Bayern are guaranteed to progress from Group B, leaving Flick to now prepare Bayern for a crucial Bundesliga clash with Borussia Dortmund.

Thomas Muller saw a couple of half shouts for penalties turned down either side of Sa reacting sharply to a low Leon Goretzka drive as Bayern started brightly.

David Alaba's untimely stumble allowed Olympiacos a rare sight at goal but Lazar Randjelovic dragged wide of the right post.

Lewandowski headed Pavard's pin-point cross straight at Sa, who was also alert to deny Kingsley Coman's improvised toe poke after a mazy run.

Pavard's awkward effort off his chest struck the post at the end of the half and Sa made a fine save from Goretzka's point-blank header shortly after the restart.

Sa was called into action again by Coman's stinging effort, but he was finally beaten in the 69th minute when the France winger's teasing low delivery from the right was cutely steered home by Lewandowski at the front post.

A more deserved-looking scoreline arrived in the final minute when Perisic rifled high into the roof of the goal after Coman's deflected cross fell into his path.