Anadolu Efes was tied after three quarters but could not keep up in the last quarter eventually losing the game. Mensah-Bonsu contributed 10 points and eight rebounds to his side's win.
The last time Besiktas won the title was in 1975. They were the fourth ranked team of the regular season with 22-8 record. Pops and his Turkish side have had an exceptional season and he will now be preparing to enter GB training camp in Houston from the 14 June.