Jamie Loeb expressed delight after reaching the quarter-finals of the Junior Girls competition at Wimbledon.
Loeb, who is 18 and from New York, trains at the John McEnroe Tennis Academy at Randall’s Island, where she "hits" with the former champion "from time to time".
Loeb took the first set against top seed Belinda Bencic on a tiebreak, but the Swiss star hit back to win the next two sets before going on to win the competition.
"I had a very good experience for my first time in a a grand slam," Loeb said. "It’s a big accomplishment.
"John McEnroe watched a few matches and said I need to get stronger. Now I’m going back to the States and hope to qualify for the US Open. I’m an aggressive player and am aiming for the top 20 in the world."
Although Jamie, 18, comes from a traditional Jewish family, she said: "I’m the only one of my siblings not to be batmitzvahed. I’ve had to make lots of sacrifices for tennis, but I’m going to college next year and I’d like to do Jewish studies".
Noah Rubin and partner Clement Geens of Belgium reached the quarter-finals of the doubles event.
The sixth seeds were beaten in straight sets by Kyle Edmund and Frederico Ferreira Silva.
"I’m very disappointed," said Rubin who has been compared to Spanish star David Ferrer.
"It’s always been my dream to become professional player, so whatever it takes to become no. one in world, that’s the path I’ll take."