The music of the Star-Spangled Banner gave way to the sounds of emcee Allen (Deejay Lefty) Pires’s turntable as the eighth annual Vineyard Streetball Classic got underway this Saturday in Niantic Park in Oak Bluffs. For the next five hours, would-be NBA stars from 14 teams — six from the age 10 to 12 division and four each in the age 13 to 14 and 15 to 18 — battled through round robin and double elimination play before the two strongest sides met in each division’s final championship game.