The former coach of Dan Evans, who knocked the 11th seed out of the US Open, said it was clear from an early age that the British player had a natural ability.
The 23-year-old, who is ranked 179th in the world, clinched a 6-4 6-4 6-2 victory against Kei Nishikori in New York.
Scott Key told ITV News: "I think this a big opportunity for him to take on this as a big move forward in his career. Undoubtedly we all knew he had the talent but I think it's actually having the belief in his own talent and that's what's changing."
More top news
The 'Bend it Like Beckham' director says Viceroy's House was inspired by the events her family went through during Partition in 1947.
The Trump administration is greatly expanding the number of illegal immigrants in the country who are considered a priority for deportation.
The feature on the Facebook-owned app is strikingly similar to similar "story" elements on Instagram and Snapchat.