Novak Djokovic was a little late to his hitting date with the young U.S. player Michael Mmoh at Wimbledon in July. But Boris Becker, Djokovic’s coach, was there, and he and Mmoh reminisced while waiting for Djokovic to arrive.

Becker fondly remembered Mmoh’s father, Tony Mmoh, who was a professional tennis player from Nigeria and had reached No. 105 on the tour. Becker told Michael, now a top junior player, about how the elder Mmoh had played, and Becker also passed along some tips.

“I know what he was saying,” Tony Mmoh said with a laugh during a telephone interview from Riyadh, Saudi Arabia, where he was working. “He was joking about who had the thickest legs on the tour, him or me.”

That was a running joke between Becker and the elder Mmoh, two stocky players who once shared the same job description. Thirty years ago, just after Becker had become the youngest Wimbledon champion, Tony Mmoh won his only U.S. Open match, beating Thomas Hogstedt in straight sets.

This week, Michael Mmoh, the No. 2 seed in the boys’ singles, will play Evan Furness of France as he looks to establish his own fortunes as a professional tennis player.

Mmoh is a member of the next wave of very promising young U.S. juniors, including Taylor Fritz, Reilly Opelka, Tommy Paul and Frances Tiafoe.

Mmoh, 17, is ranked No. 2 by the International Tennis Federation behind Fritz.

“Michael is one of the most athletic people you will ever see on a tennis court,” said Opelka, his close friend, who is ranked No. 5. “There is nothing he can’t do out there.”

Although Mmoh is part of the promising group of U.S. teenagers, he could choose to play for several countries, including Nigeria, Ireland, Australia and, perhaps, Saudi Arabia.

His mother, Geraldine O’Reilly, is from County Monaghan in Ireland, but she is also an Australian citizen, as is Michael through her. O’Reilly, an avid tennis fan, was working in Saudi Arabia as a nurse in the 1990s when she met Tony Mmoh, who was coaching the Saudi Arabian Davis Cup team. Michael was born and grew up in Riyadh, where his family lived in a compound for international residents.

Tony Mmoh grew up in Lagos, Nigeria, and played tennis at a club there with his uncle. He moved to North Carolina to play at St. Augustine’s College (now St. Augustine’s University), and while there he became a U.S. citizen and became infatuated with Michael Jordan, after whom he named his son.

So Michael Mmoh is an American-Irish-Nigerian-Australian from Saudi Arabia, with an immense serve.

He began playing tennis at 3, but his father said he had noticed Michael’s ability well before that.

“No one believes this story,” Tony Mmoh said, “but I will tell you anyway.”

Apparently, when Michael Mmoh was 8 months old, his older sister knocked over a basket of tennis balls. Michael, who was sitting on the floor, reached out and blocked a ball.

“I could not believe this,” Tony Mmoh said. “So I rolled out another one, and he did the same thing. I told his mother, this boy is special.”

The elder Mmoh said that Michael’s older sister could have been a world top-10 player if she had had the same love for tennis that Michael has, but she did not. Michael has had a passion for sports from the start.

“Sometimes I would hear a noise at like 2 in the morning and I would go downstairs,” Tony Mmoh said. “The door would be open, and I asked Michael why. He told me he had been outside playing basketball.”

Eventually, the Mmohs moved to Washington, and Michael trained at the IMG Academy in Bradenton, Florida. His favorite athlete was not Jordan, though. It was Andy Roddick, and like Roddick, Mmoh uses his serve as his most potent weapon.

This year, Mmoh made the semifinals of the juniors at the Australian Open and the French Open before winning the juniors tournament at Roehampton leading up to Wimbledon, where he lost in the third round.

Perhaps more memorable, though, was hitting with Djokovic at Wimbledon. After they practiced the first time, Djokovic asked Mmoh to warm him up for his semifinal match against Richard Gasquet. Djokovic went on to win Wimbledon, but it was not the first time a member of the Mmoh family had helped a champion.

Tony Mmoh played in the 1988 Olympics for Nigeria, and while in Seoul, South Korea, he hit with Steffi Graf. She won the Grand Slam that year, and then won the gold medal, too.

“I cannot take credit for that,” he said.

Tony Mmoh now runs a sports management firm and has been working in Saudi Arabia starting a league for futsal, a primarily indoor variation of soccer. He said he hoped to rejoin his son on tour soon. But for now, when Michael needs help, as he recently did with his serve, he sends video to his father for analysis.

Like the USTA, Tony Mmoh harbors great hope for his son, and he said he wanted Michael to advance further than he had. It helps that Michael, who began swatting tennis balls before his first birthday, had a good start.

“He felt like he started too late as a player,” Michael Mmoh said of his father. “He was too passive and hit too many slice backhands. He wants me to be more aggressive, and I’m very happy to do that.”