Real Madrid opened their Euroleague account by beating Panathinaikos 85-78 in the Spanish capital after coming from behind.
For the Greeks, this was a game that got away from them, especially in the last quarter, as Real erased a 44-35 half-time deficit and then 60-59 heading in to the fourth period to come up trumps.
Former NBA star Rudy Fernandez was unstoppable with 23 points helped by 18 points from Nikola Mirotic, 10 coming from the free-throw line.
"It has been an important win because we managed to beat a good, rebuilt team like Panathinaikos," Madrid coach Pablo Laso said. "We lost the advantage we had in the second quarter. We improved our defence when we got back from the locker room and played a more attractive basketball."
Sofoklis Schortsanitis led Panathinaikos with 23 points, shooting a perfect 9/9 from the field.
Besiktas began life in the Euroleague with a comfortable 81-65 home win over a youthful Partizan side.
Five three-pointers from Patrick Christopher set the tone for the win as the Turkish side never looked in danger against the Serbian champions despite losing on the boards 33-27.
Partizan were led by Vladimir Lucic, who hit 18 points.
Alba Berlin scored a big away win at Montepaschi Siena by winning 92-82 in Italy.
The Italian champions are rebuilding a new-look squad this year and it showed as they looked out of sorts as the organised Berlin side picked them apart.
Guard DeShaun Wood led the Germans with 15 points, supported by Nihad Djedovic's 14 points.
"It was a very important win for us, especially because we are a new team in the Euroleague and Siena's tradition in this court is very important and to come and win here is really difficult," Djedovic said afterwards.
David Moss led Montepaschi with 17 points.
Barcelona got off to a winning start as they defeated Brose Baskets 72-60 as aa 26-9 opening ten minutes set the tone for what was to come. Bamberg had no answer for the duo of Pete Miickeal and Ante Tomic, who each scored 12 points to lead the Catalan side. The latter also grabbed nine rebounds.
Brose were led by Bostjan Nachbar, who was the only Bamberg player in double digits with 20.
EA7 Milano started their Euroleague campaign with a narrow 80-75 win over Anadolu Efes. Ioannis Bourousis led the Italians with 23 points and seven rebounds. The Turkish side were led by Jordan Farmar's 19 points and six rebounds.