US Open Wawrinka downs Del Potro

Kei Nishikori stunned Andy Murray to reach the US Open semi-finals, holding his nerve in a gripping final set to move two wins away from becoming the first Asian man to capture a Grand Slam singles title. Japanese star Nishikori clinched a dramatic 1-6, 6-4, 4-6, 6-1, 7-5 comeback triumph in a shade under four hours against the Wimbledon and Olympics winner and 2012 US Open champion.