Galatasaray and Panathinaikos got their Top 16 campaigns off to winning starts with victories in the opening matches on Tuesday.
Turkish side Galatasaray defeated Zalgiris Kaunas 78-69 in Group E, in a match played in front of an empty arena.
Galatasaray were hit with a crowd ban after a fan was stabbed to death in violent scenes ahead of their meeting with Crvena Zvezda last month.
The home side's Kerem Gonlum was pleased with the victory, but he lamented the lack of support inside the stadium.
"First of all I have to say that it's really hard to play without fans," he said.
"We had a bad start to the game and it went on like that for the whole first half. We knew that we had to take chance on defence and we did that well in the second half.
"We forced them to make mistakes and it worked really well for us. We are happy to start the Top 16 with a win.
And Sinan Guler echoed the sentiments of his team-mate: "To win at home is important, even if we didn't have our fans.
"We were slow in the first half and didn't play the basketball that we wanted to play. But with a lot of hustle in the second half we got a good win today.
In the other clash in Group E, Panathinaikos ran out 83-76 winners over Maccabi Tel Aviv.
The Greek side were four points behind heading into the final quarter, but produced a superb final period to turn the match around and ensure they began in victorious fashion.