The Greek giants need only to beat bottom-basement DKV Joventut in Wednesday's final Top 16 Group E match, while Partizan Belgrade must hope that Olympiacos lose by less than 35 points.
On the off chance that Joventut can upset Olympiacos by 35 points or more in Piraeus, Greece, then Badalona will go through to the final eight regardless of their own result against defending champions CSKA Moscow.
"For the team of DKV Joventut, tomorrow's game is quite an easy game as they have nothing to lose. On the other hand, for us it is a very difficult and dangerous game," said Olympiacos boss Pinhas Gershon.
"If we manage to play cleverly, without so many mistakes, we are going to take the thing that we want. The key of the game will be the mistakes."
Olympiacos are without big-man Ryan Stack for three weeks due to a foot injury, but will again rely on Top 16 scoring sensation Scoonie Penn to improve their record to 4-2 and secure a place in the next round.
Joventut, meanwhile, are again without Lubos Barton, but will hope that Rudi Fernandez can continue to maintain his fourth-best Top 16 scoring average of 16.2 points-per-game.
With their fate completely in the hands of Joventut and Olympiacos, Partizan Belgrade will still be hoping to overturn CSKA Moscow's 16 game Euroleague winning streak and secure a 4-2 Top 16 record.
The raucous Belgrade crowd should play a big role in Partizan's hopes of preventing CSKA from securing a perfect Top 16 record.
The hosts will be at full strength for the encounter, while CSKA will again be without David Vanterpool, while David Andersen and Oscar Torres are still questionable after returning to practice on Monday.
With Tau Ceramica and Maccabi Elite having already secured their quarter-final places out of Group D, their matches against Pau Orthez and Lottomatica are inconsequential.
Having already secured the top seed, Tau coach Bozidar Maljkovic will rest guards Fred House and Pablo Prigioni against Pau, though Luis Scola and Serkan Erdogan will return to the line-up.
In Tel Aviv Will Bynum could miss the Top 16 finale against Roma for personal reasons, while Nikola Vujcic is questionable with a hamstring injury.
Guard Mire Chatman is out with a hand injury for the visitors.
Follow LIVE coverage of Thursday's Group D and E finales starting with Maccabi Tel Aviv v Lottomatica Roma from 19:45 CET!