Leonardo ##erer beats Joao masters in longest Davis Cup singles match . Argentine wins in six hours 43 minutes -- third - longest in masters history . Britain beats masters in first round , with Andy Murray defeating John Isner . quarterfinals , semifinals , Kazakhstan , Belgium , Serbia also reach quarterfinals .
Leonardo Mayer beats Joao Souza in longest Davis Cup singles match . Argentine wins in six hours 43 minutes -- third-longest in tennis history . Britain beats U.S. in first round , with Andy Murray defeating John Isner . France , Australia , Kazakhstan , Belgium , Serbia also reach quarterfinals .