Taylor Fritz says he has proven to himself that he ‘belongs’ among the tennis elite after a truly breakthrough season on the ATP Tour. The US number one has won a maiden Masters this season as well as breaking into the top ten for the first time. That led to a first appearance at the ATP Finals, where he impressed again in getting to the semi-finals.He also helped Team World to a first success at the Laver Cup and reached the last eight at Wimbledon in what was just a generally excellent season. Fritz, though, says that while he is understandably delighted with how the year has gone, he still sees a lot of room for impro …