Having come from behind to defeat Vikingur Reykjavik in the play-off round, Rui Vitoria’s side looked to dominate the early stages against Fiorentina.
The hosts’ bright start was duly rewarded with a breakthrough inside five minutes, as Nemanja Maksimovic’s clever pass on the edge of the box was brilliantly swept into the top corner by Karol Swiderski.
Armed with the momentum, Maksimovic doubled Panathinaikos’ lead in the 19th minute, with the Serb pouncing on a mistake from Pietro Terracciano to tap home from close range.
Undeterred by the hosts’ rapid start, Fiorentina immediately went in pursuit of a response, and Raffaele Palladino’s men delivered in spectacular fashion, netting twice in the space of three minutes to draw level.
First, Lucas Beltran headed Robin Gosens’ inviting delivery into the top corner before Nicolo Fagioli restored parity with a powerful drive that deflected beyond the helpless Bartlomiej Dragowski.
After a frantic opening half-hour, both teams settled into a more sedate rhythm with half-time approaching, as Matias Moreno’s close-range finish was ruled out for offside, leaving the sides level at the break.
The early stages of the second half followed a similar pattern to the first with Panathinaikos firmly on top, and their pressure paid dividends when Filip Djuricic’s cut-back was clinically dispatched into the bottom corner by Tete for his 11th goal of the season.
That spurred the hosts on with time ticking into the final 25 minutes, but Terracciano stood firm in the Fiorentina goal to thwart Azzedine Ounahi’s deflected strike.
Determined to increase their advantage before next week’s return leg in Florence, the Shamrock continued to commit numbers forward and they came within inches of scoring a fourth when Duricic curled agonisingly against the inside of the post late on.
That was ultimately as close as either side came to altering the scoreline in the closing stages, with both defences holding firm as Fiorentina’s dismal record against Greek opposition extended to just one win in seven (D3, L3).
Flashscore Man of the Match: Filip Djuricic (Panathinaikos)