Watch: Alexander Zverev seals semi-final place with vital victory over America's John Isner
Watch the best shots from Alexander Zverev’s win over John Isner at the ATP Finals in London, setting up a semi final showdown with Roger Federer.
Watch the best shots from Alexander Zverev’s win over John Isner at the ATP Finals in London, setting up a semi final showdown with Roger Federer.