Francis Tiafoe literally grew up around tennis, often spending nights at a Maryland tennis center where his father worked. At only 16, he is ranked number two in the world. Could a future U.S. champion be in the making? (Lee Powell/The Washington Post)

Francis Tiafoe’s introduction to Wimbledon couldn’t have been more fitting.

Scheduled to open play Saturday afternoon in the Junior Championships, as Wimbledon’s tournament for 18-and-under players is known, Tiafoe arrived at the practice courts for a 12:30 p.m. warmup just as it started raining.

After the skies cleared, he trudged back to the practice court, but the skies opened again before he hit the first ball.

Finally, after whiling away the afternoon in the junior players’ lounge listening to music, reminding himself to drink water and guessing how much to eat, Tiafoe was informed that his first-round match had been postponed until Monday, along with several dozen other matches, because of scheduling havoc wreaked by the weather.

“You see it so much on TV, the rain delays at Wimbledon,” Tiafoe said. “This was the first time I experienced one. It’s not easy, but you’ve got to stay focused and be ready to go.”

Tiafoe, of Riverdale Park, has spent most of his 16 years in a tennis bubble, having picked up the game at 5 while his father worked as a maintenance man at College Park’s Junior Tennis Champions Center. But he had never set foot on a grass court or owned a pair of grass-court shoes with pimpled soles until two weeks ago, when he and a contingent from the JTCC flew to London to compete in a Wimbledon tuneup at nearby Roehampton.

Frank Salazar, the center’s director of high-performance training, prepared the youngsters — Tiafoe, 16-year-old Raveena Kingsley and the Arconada siblings, Usue, 15, and Jordi, 17 — for the quirks of grass-court tennis as best he could. All earned spots in Wimbledon’s 64-player boys’ and girls’ draws.

Salazar warned them that the ball wouldn’t bounce as high, so they needed to bend their knees and stay low to the ground. He advised them to shorten their backswings to quicken their reaction time. And then he let them hit — just for fun to get a feel for it, and then in a more structured way.

As the No. 7 seed here, Tiafoe is finding out that competing on grass is something he must learn by doing, with a racket in hand and sod underfoot.

“I had some good practice at Roehampton,” said the 6-foot-1 Tiafoe, who lost in the tuneup’s second round. “The movement is not as easy. You have to have a lower center of gravity. The ball doesn’t bounce as much. And the courts move a little faster than normal. But I like to play fast, so it helps.”

Grass favors the agile athlete with nimble feet and exceptional balance. And it rewards the aggressor who hits the ball flat, serves big and seizes opportunities to move forward.

Some players take to it at once. Bjorn Borg and Roger Federer are among the former Wimbledon boys champions who went on to claim multiple Wimbledon titles as adults. Others, like clay-masters Chris Evert and Rafael Nadal, forged themselves into Wimbledon champions by force of will, altering their strokes and tactics to suit the surface.

Adapting to grass-court tennis is one thing. Adapting to the pressure of competing at Wimbledon’s All England club is another.

What struck Tiafoe upon stepping into the idyll he had only seen on TV was how big the grounds were. He had no idea it encompassed 19 courts, in addition to Centre Court, plus 22 practice courts largely obscured from public view.

He also couldn’t believe the number of tennis-mad fans jammed onto the hillside now called Murray Mound, in honor of the Scot who last year snapped a 77-year drought of British men’s Wimbledon champions.

“To get to see it live for the first time, it’s an extraordinary feeling,” Tiafoe said.

Whether Tiafoe will get a chance to compete one day in Wimbledon’s main draw is an open question.

“He’s young,” Salazar said, “and it’s a long road.”

As the No. 1 seed in his debut at the Junior French Open earlier this month, Tiafoe fell to an unseeded German in the second round. He has since slipped to No. 8 in the world rankings.

But from Salazar’s vantage point, that has helped Tiafoe relax more heading into Wimbledon, relieved of the spotlight and scrutiny that come with being the top seed.

“These tournament are tough,” Salazar said. “Everybody is good. Everybody can play well. Everybody hits the ball hard. Everybody is strong. You have to be really focused and prepared to play each match when you take the court.”