A buzzer-beating lay-up from Stratos Perperoglou gave Barcelona a pulsating 100-99 win in game one of the Liga Endesa finals in Catalonia.
Perperoglou played the supporting role with 18 points with Justin Doellman leading the winners with 19.
Jaycee Carroll led all scorers with 21 points for Real Madrid.
Game two is in Barcelona on Friday.
