Argentinian powers to 2-6, 6-4, 6-4 victoryHeat and humidity take toll on DjokovicThe scoreboard did not yet indicate that anything was awry, but even as Novak Djokovic led by a set in his opening mat

Novak Djokovic suffered defeat and struggled physically in his first match since Wimbledon as he was upset by Thiago Agustin Tirante in a sapping three-set contest at the Cincinnati Open.