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)

To earn a spot in Tuesday’s final of the Citi Open Wild Card Challenge, top-seeded Francis Tiafoe had to beat a Sidwell Friends standout Monday morning and get past an all-American from South Carolina in the afternoon.

Tiafoe’s most formidable challenge, however, was reining in the emotions that threatened to derail him after he questioned a line call during his semifinal against Andrew Adams, 21.

Tiafoe, 16, thought he had hit a forehand winner, but Adams, who recently reached the NCAA championships’ round of 16, called the ball out, with Tiafoe serving up a game after three successive service breaks in the opening set.

A U.S. Tennis Association supervisor confirmed the call. But Tiafoe, who proceeded to get broken again, needed several games before he stopped muttering under his breath and regained his focus in front of an audience he wanted to impress.

In the end, Tiafoe’s biggest weapon — his quick-strike forehand — trumped Adams’s steadier game and demeanor. And the Riverdale Park resident rolled to a 6-4, 6-3 victory to advance to Tuesday’s final at College Park’s Junior Tennis Champions Center.

The setting wasn’t nearly as grand as Roland Garros, the Parisian home of the French Open, where Tiafoe competed earlier this month as the top seed in the Grand Slam junior event and served as sparring partner to world No. 1 Rafael Nadal for three days running.

And Monday’s crowd wasn’t nearly as large or discerning as a Grand Slam audience, consisting of several dozen young players who regard Tiafoe as a role model, fellow juniors, collegians, parents and tennis enthusiasts who had come to watch the local phenom.

But it amounted to very real pressure in Tiafoe’s last competitive event before he heads to England for a grass-court tuneup in advance of his debut in Wimbledon’s junior tournament.

“I was going into the match really focused and really trying to win this match,” Tiafoe said afterward. “After that call [at 4-3], I thought I played pretty well. I was hitting the ball well and hitting my forehand pretty well the whole match.”

Tiafoe will face frequent training partner and good friend Jordi Arconada, who turned back La Plata’s Aaron Gomez, 4-6, 7-5, 6-2, and then dispatched the District’s Vijay Paul, 6-3, 6-3, to land his spot in the final.

Tuesday’s victor will earn a wild-card entry into qualifying for the July 26-Aug. 3 Citi Open, Washington’s hard court tournament at William H.G. FitzGerald Tennis Center in Rock Creek Park.

Tiafoe, who has trained since age 5 at the College Park tennis center, reached the final without dropping a set. Earlier Monday, he defeated Jacob Walker, 16, a rising junior at Sidwell Friends, 6-3, 6-4.

Tuesday’s women’s final will pit second-seeded Usue Arconada against fourth-seeded Skylar Morton. Arconada led, 6-0, 3-1, when her semifinal opponent retired because of an injury. Morton advanced on a walkover when top-seeded Kateryna Yergina also pulled out because of injury. Both had earned straight-sets quarterfinal victories earlier in the day.