After both teams safely made it through the second round, the Greek giants host the first leg in Athens, with a playoff place against either Bodo/Glimt or Jagiellonia Bialystok ultimately at stake.
Match preview
Finishing fourth in last season's Greek Super League playoffs saw Panathinaikos secure a European return for 2024-25, and they kicked off their latest continental campaign by beating Botev Plovdiv of Bulgaria in the Europa League's second qualifying round.
Having run out 2-1 winners on home soil, the Greens then cruised to a 4-0 away win one week later, with Swedish striker Alexander Jeremejeff scoring three goals across the two contests.
Former Inter Miami and Sevilla boss Diego Alonso took the role of head coach following Fatih Terim's departure in May, and the Uruguayan has been tasked with challenging for the title and securing group-stage football for his new club.
Panathinaikos came within a whisker of reaching the Champions League last year, only to fall to Braga in the playoffs, then made the group phase of the Europa League, where they posted only four points from six matches against Rennes, Villarreal and Maccabi Haifa.
Finalists in the 1971 European Cup, which they lost to none other than Ajax at Wembley, the Athens club have a proud history in UEFA competition - but their next opponents' is even more impressive.
That victory in London was the first time Ajax had been crowned European champions, beginning a three-year period of domination, and they claimed top spot again by winning the 1994-95 Champions League - most recently, Erik ten Hag's team came close to the final in 2019.
New coach Francesco Farioli - who arrived from Nice in the off-season - now has the tough task of rebuilding after the Amsterdam club finished fifth in the Eredivisie last term, which was some feat given a dismal start that saw them struggle at the foot of the table.
Hoping to put a period of on and off-field turmoil behind them, Ajax returned to competitive action in their opening Europa League qualifier last month, beating Vojvodina 4-1 on aggregate in the second round.
After ekeing out a 1-0 victory in the first leg at home, they were 3-1 victors in Serbia, where Josip Sutalo, Jorrel Hato and Bertrand Traore all scored during the second half.
Set to begin their new league campaign against Heerenveen this weekend, Ajax have now put together six straight victories including pre-season, when Rangers and Panathinaikos' domestic rivals Olympiacos were among their victims.
With stars such as Hato and Brian Brobbey staying at the club - at least so far - Farioli's new era promises much, but the stakes will be far higher on Thursday.
Panathinaikos Europa League form:
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Ajax Europa League form:
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Team News
Summer signings Sverrir Ingi Ingason, Nemanja Maksimovic and Tete were all involved in the win over Botev Plovdiv last time out, and fellow Panathinaikos new boy George Baldock could also make an appearance on Thursday evening.
After impressing at Euro 2024, Slovenian midfielder Adam Gnezda Cerin should start in the hosts' engine room, but international teammate Andraz Sporar may have to play second fiddle to Alexander Jeremejeff up front.
The latter scored seven goals in 14 league games during the second half of last season and already has three strikes to his name in Europa League qualifying.
Meanwhile, Ajax will be without goalkeeper Geronimo Rulli, who is still on leave after competing at the Olympics with Argentina, so Diant Ramaj will vie with 40-year-old Remko Pasveer to start between the posts.
Owen Wijndal (arm) and Gaston Avila (knee) must miss the trip to Greece through injury, but Netherlands internationals Brian Brobbey and Steven Bergwijn may travel after returning to training last week.
The visitors are likely to deploy Chuba Akpom at the tip of their attack, with Jordan Henderson and Kenneth Taylor playing key roles in midfield; albeit Steven Berghuis and Branco van den Boomen are both pushing for promotion from the bench.
Panathinaikos possible starting lineup:
Dragowski; Baldock, Ingason, Jedvaj, Mladenovic; Cerin, Arao; Tete, Bakasetas, Djuricic; Jeremejeff
Ajax possible starting lineup:
Pasveer; Rensch, Sutalo, Baas, Hato; Taylor, Henderson, Van den Boomen; Ramsussen, Akpom, Berghuis
We say: Panathinaikos 1-1 Ajax
It is fair to say that neither club is the force they were during the 1990s, or at other successful stages during their illustrious history, but this still represents a heavyweight clash in Europa League qualifying.
A close-fought first leg should see the spoils shared in Athens, leaving Ajax slight favourites to prevail after next week's return.