By Martyn Herman RIO DE JANEIRO, Aug 19 (Reuters) - American Connor Fields powered home to Olympic BMX gold after a thrilling final at the X Park on Friday. Fields trailed compatriot Nicholas Long at the halfway point of the final but produced a stunning couple of turns to take the title from Dutch rider Jelle van Gorkom. Colombia's Carlos Alberto Ramirez Yepes was third after edging out Long in a photo finish. An ecstatic Fields, who recovered from a badly broken hand in April, threw down his bike in the finish area and leapt into the arms of his support team. ... More...