Croatia's American-born playmaker Dontaye Draper hit his only field goal of the game on the buzzer to give Real Madrid a 76-73 home win over Germany's Bamberg while Barca ground out a 71-69 success against Khimki Moscow to also improve to 8-1.
Serbian centre Nenad Krstic scored 20 points as CSKA beat Alba Berlin 80-65 at home.
Holders Olympiakos Piraeus boosted their hopes of reaching the knockout stage with an emphatic 79-60 win at Besiktas Istanbul while Maccabi Tel Aviv stayed in contention with a rollercoaster 66-62 success at Caja Laboral Vitoria, who suffered their fifth successive loss.
Italians Montepaschi Siena won 87-69 at home to Fenerbahce Istanbul, while 1999 winners Zalgiris Kaunas rekindled their own hopes with an 83-67 away rout of Unicaja Malaga.
The second group stage of the competition features two pools of eight teams, of which the top four from each pool will advance to the best-of-five quarter-final playoff series.
The playoff winners will progress to the May 10-12 Final Four at London's O2 Arena.