While Olympiacos will be participating in their first competitive encounter of the season, Genk have already lost out in the Champions League.
Match preview
Olympiacos have been used to winning Greek titles in recent years, giving them every opportunity to compete at European football's top table.
However, the Red-Whites were only able to muster a third-placed finish in 2022-23, leaving them requiring to win at least one qualification tie to guarantee group-stage action on the continent.
With domestic action yet to get underway, Diego Martinez's side have instead participated in a number of friendlies, impressing during a recent 3-1 victory over Rangers.
Three days on from that triumph, though, Olympiacos were on the receiving end of a 2-0 defeat to English second-tier side Norwich City, highlighting that much improvement will be required to compete on this stage.
A wide array of new arrivals have been made this summer, including that of Ecuador star Jackson Porozo and Greece international Sotiris Alexandropoulos.
Meanwhile, Genk have been looking for a response from dramatically losing their grasp of the Belgian title on the final day of last season.
Instead, they have endured a disappointing start to 2023-24, losing one of their opening two league fixtures and already bowing out of the Champions League.
Wouter Vrancken witnessed his side play out two draws with Servette before succumbing to the Swiss side on penalties, a setback which was then followed by a surprise 1-0 home defeat to Eupen.
Although Genk have seemingly bought well this summer, this team is yet to gel, and such a factor may level up a tie against opponents who are in need of competitive action.
Genk form (all competitions):
Team News
Barring any fitness issues, the assumption is that Martinez will name close to the same Olympiacos XI that begun the defeat to Norwich.
Although six changes were made at either half time or on the hour mark, the players who were given the bulk of the minutes seem likely to start here.
If that is the case, though, only veteran midfielder Vicente Iborra would be in line to make his debut for the Greek giants.
Vrancken made mass changes for Genk's league game with Eupen due to the three-day turnaround, that decision not paying off as his team suffered a surprise defeat.
With that in mind, he could revert back to the team that faced Servette last week, with the likes of teenage new arrival Christopher Bonsu Baah having to settle for a place among the replacements.
Olympiacos possible starting lineup:
Tzolakis; Rodinei, Retsos, Ndoj, Ramon; Iborra, Bouchalakis; Vrousai, Biel, Masouras; Kamara
Genk possible starting lineup:
Vandevoort; Munoz, Cuesta, McKenzie, Kayembe; Heynen, Hrosovsky; Paintsil, El Khannouss, Tresor; Arokodare
We say: Olympiacos 1-1 Genk
Although Genk have the greater match fitness in their legs, we cannot ignore that they have earned mixed results during their opening quartet of fixtures. With home advantage in their favour, Olympiacos may do enough to match their opponents and earn a share of the spoils.