"I'm really happy. The team has made history. Mendilibar has made us a strong team. He told us we have to play as a family," said midfielder Santiago Hezze.

Mendilibar, 63, became the Greek side's third manager of the season when he took over the reins in February and he now has back-to-back European trophies after winning the Europa League with Sevilla last year.

Both sides started with great intensity as Daniel Podence forced a fine save from Fiorentina goalkeeper Pietro Terracciano, before Andrea Belotti missed his kick when presented with a good opportunity at the other end.

Fiorentina briefly thought they had taken the lead after nine minutes but Nikola Milenkovic was immediately flagged for offside when he turned home a cross past Olympiakos' Konstantinos Tzolakis.

Greek goalie Tzolakis made a fine save at the feet of Giacomo Bonaventura soon after and Nicolas Gonzalez later completely mistimed his volley when well positioned as Fiorentina had the better of the first-half chances.

Sights on goal dried up in the second half, though Tzolakis did come to Olympiakos' rescue again on 69 minutes when he adjusted well to leap backwards and palm away Christian Kouame's scuffed, bouncing effort.

Olympiakos veteran Vicente Iborra nearly broke the deadlock with a header from a free-kick that flew just wide of the Fiorentina goal in the last 10 minutes.

But this was the last big chance of regulation time as the match ebbed its way inevitably to extra time.

- Party in Athens -

Olympiakos appealed vainly for a penalty four minutes into extra time, but the defender's arm was adjudged to be in a natural position when Stevan Jovetic's cross struck it just inside the box.

Ex-Fiorentina icon Jovetic, introduced from the Olympiakos bench, forced a good save from Terracciano with a curling 20-yard strike one minute later as the match seemed to spark back to life.

However, the game then tightened up again as neither team appeared to want to take a risk that might cost them the tie.

Penalties seemed certain until the 116th minute when El Kaabi stooped to head home Hezze's cross for his 16th goal in European competition this season.

The roar that greeted the validation of El Kaabi's goal, following a lengthy VAR check, in the 120th minute from the majority Greek fans in Athens showed what the occasion meant to the club.

"Amazing. For Olympiakos and me. Really proud of my guys. We did great all year and deserved it," Jovetic said to TNT Sports.

The Montenegrin attacker added that the party tonight in Olympiakos' hometown of Athens "will be amazing".

For Fiorentina, it meant defeat in consecutive Europa Conference League finals following a 2-1 loss to West Ham in 2023 after Jarrod Bowen's 90-minute winner.

"I have to compliment Fiorentina, two years in a row. A shame for them," added Jovetic,who played for the Tuscan side from 2008-2013.