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)

Every summer for eight years, Francis Tiafoe came to the Citi Open as a spectator. He would sometimes stand behind the black wire fencing at the practice courts to watch players warm up, his fingers interlaced in the fence’s holes as he got as close as he could to the court. Then he would sit in the stands with his coach during the matches.

Tiafoe wasn’t part of the crowd for the start of this year’s Citi Open, but one followed him as he practiced at William H.G. FitzGerald Tennis Center on Saturday and Sunday. Receiving a wild-card berth in the main draw, the Riverdale Park native will make his debut in an ATP Tour main draw near his home. Tiafoe will play Evgeny Donskoy on the Stadium Court on Monday night.

“It’s a big step, but you don’t want to put too much pressure,” Tiafoe said. “You don’t want to overthink it. It’s just going to be another tournament but playing against pros.”

The 16-year-old won the Citi Open Wild Card Challenge in June, earning an entry into qualifying. Tiafoe got word Thursday night that tournament officials decided to give him a wild-card entry, allowing him to skip this weekend’s qualifying tournament.

“From a tennis perspective, obviously he’s from here and he trains here,” tournament director Jeff Newman said. “We thought with the crowd support, it was the right opportunity at the right time. We thought it was good for all parties, and we look forward to his match. I think he’s going to perform well.”

Misha Kouznetsov, Tiafoe’s coach at the Junior Tennis Champions Center in College Park, heard the news Friday morning. On their way to the courts to train, he reminisced about all of the times he and Tiafoe had gone to the Citi Open as fans. After years of competing in junior tournaments in and around the District, the Citi Open will feel familiar to Tiafoe. He will be around the same ball boys as other local tournaments, and among the crowd will be friendly faces from the JTCC.

During his practice sessions this weekend, he drew a larger crowd than the professionals beside him, including Sloane Stephens, the top American in the women’s field. “I think this is the junior kid who’s really good,” one woman said as she walked by his practice court. Two ball boys watched Tiafoe hit Sunday morning, both of them a year older than him.

“This is our tournament,” Kouznetsov said. “I think he’s comfortable. It’s incredible. We’re pumped to be here. A lot of people will hopefully come watch him play.”

Tiafoe got to the tournament site a little after 8 a.m. on Saturday to check in. He stood at the back of the long line for credentials until someone told him players should move to the front. Kouznetsov signed him up for a practice session against Yen-Hsun Lu, ranked No. 42 on the ATP Tour and seeded 16th in the tournament.

Kouznetsov said the practice session was one of the most intense Tiafoe has had. Some pros don’t want to do much more than hit down the middle and do some cross-court shots the week of a tournament, but Lu wanted to go through a full training session because he has a first-round bye.

“After a while that we were playing, he said, ‘How old are you?’ And I was like, ‘16.’ He said, ‘Wow, you’re really good,’ ” Tiafoe recounted. “He was telling me to keep it up and keep the intensity high.”

Kouznetsov was beaming after Saturday’s practice, excitedly detailing how the two pushed each other and how Tiafoe was able to hold his own.

“Francis felt a little tired, but so was the other guy,” Kouznetsov said.

Then he stopped talking because he suddenly saw Lu in the player’s gym, sprinting on the treadmill.

“Oh my god, this guy is now on the treadmill,” Kouznetsov said. “I’ve got to show Francis this. We’re learning every minute.”

Another part of the learning process this week is balance, something the other professionals won’t have to worry about. Tiafoe’s tennis schedule has made him fall behind on schoolwork, so he has opted for morning practice sessions at FitzGerald Tennis Center with five to six hours of studying in the afternoon.

Disappointing losses in the junior fields at the French Open and Wimbledon, where Tiafoe showed signs of immaturity, also provided valuable lessons for this week. Kouznetsov said Tiafoe has nothing to lose but a lot to gain from this experience.

“Leaving Wimbledon, I wasn’t too happy,” Tiafoe said. “I’ve just been trying to be as professional as possible. I’ve got to act like a pro when I’m playing these pros.”