Energa Torun required double overtime to beat Spanish club side Mann Filter (87-79).
Kiesha Brown from Mann Filter took the game into overtime (67-67) with the last points in regulation time.
Mann Filter were 11 seconds away from taking the game during the first overtime when the hosts were saved with a triple by Jelena Maksimovic (22 points).
Energa Torun led all through the second overtime and are now 2-0 in Group J. Aneika Henry had a game high 27 points in a losing cause.
Shay Doron scored 19 points and Le'Coe Willingham added 18 points and 12 rebounds as Elitzur Ramla opened their EuroCup Women campaign with a victory (82-69) against HATIS Yereva.
Partizan Galenika got past Besiktas - that have Lucie Bouthors, a former French youth international - to win (73-61). Dajana Butulija did most of the offensive damage with 17 points while Jasmine Stone controlled the rebounds with 13.
Results from day 2
Zeljeznicar 73-58 Lemminkainen BC Horizont 92-53 SCM-CSS Craiova ZKK Partizan Galenika 73-61 Besiktas JK HATIS Yerevan 69-82 Elitzur Ramla Minsk-2006 116-50 Petrolina AEK Nantes Rezé 83-41 Vagos Saarlouis Royals 77-79 Seat Györ ESB Lille Metropole 85-60 Olivais Coimbra Lotto Young Cats 62-69 Ruzomberok Energa Torun 87-79 Mann Filter Reyer Venezia 64-61 Arras Szeviép 72-75 Gran Canaria