H.D. Woodson senior Antwan Walker (15) throws down a dunk during the Warriors’ DCIAA title game victory over Theodore Roosevelt. (Katherine Frey/The Washington Post)

H.D. Woodson senior Antwan Walker stepped out of the rental car last April and was star-struck. Duke men’s basketball Coach Mike Krzyzewski walked past him in the parking lot just days after leading the Blue Devils to the 2015 national championship.

Walker and Woodson boys’ basketball Coach Trey Mines had trekked to the Dallas suburbs so Walker could play in his first national event at a shoe-sponsored tournament with a Richmond-based AAU team. The slender 6-foot-7 star had just been named D.C. Interscholastic Athletic Association player of the year after leading the Warriors to their first league title, but Mines kept reminding him “nobody knows you still.”

When Walker walked inside, he wasn’t the tallest person in the gym anymore. Everyone on the floor could dunk like him. College head coaches he had seen only on television watched his team play. By the time Walker got home, seven Division I coaches had called Mines asking to set up a workout. D.C.’s best kept basketball secret was out.

“Dude,” Mines told Walker at the time, “there’s a whole different world of basketball than what you see in D.C. public school basketball.”

Walker’s rise as a recruit has coincided with the Warriors’ ascent to the top of the local boys’ basketball scene. No. 1 Woodson (31-0), which faces No. 14 Gonzaga on Thursday at Verizon Center in the D.C. State Athletic Association tournament semifinals, is just two wins shy of becoming the first city public school boys’ basketball team to finish a season undefeated since Spingarn accomplished the feat in 1985 with future NBA player Sherman Douglas.

But Douglas was a household name, even before the proliferation of websites and tournaments that dominate the recruiting landscape today. Walker, 17, didn’t play his first organized game of basketball until he joined Woodson’s junior varsity team as a freshman.

Only when Walker experienced a growth spurt before his sophomore year did Mines understand he might have found the late bloomer to push the Warriors to another level.

Antwan Walker has emerged as a force on both ends of the floor for the Warriors. (Mark Gail/For The Washington Post)

Walker’s rim-rattling dunks provide the flash in H.D. Woodson’s often deliberate offense. (Doug Kapustin/For The Washington Post)

Walker was raw and barely talked in front of strangers, but he already could jump higher than anyone in school. His awareness, skill set and athleticism seemed to improve with each passing month. By the end of his sophomore year, he had become Woodson’s best player. Last season, he evolved into the city’s top performer, and his passion for the game strengthened.

“It just feels right, like I’m supposed to be there,” Walker said. “It’s like I’m supposed to be in the gym every time I’m in the gym. It feels like I can just come to it any time.”

His elevated profile brought unfamiliar faces as local AAU teams began lining up to convince Walker to play for them in the offseason. But growing up in Southeast Washington in a single-parent household, raised by his mother, who works two jobs as a hairdresser and cashier, Walker had always been wary of trusting new people.

He clams up in front of reporters and gets shy around college recruiters. These traits served him well in a basketball recruiting hotbed such as Washington. While adults he hardly knew kept calling and making house visits, trying to convince him what would be best for his future, Walker chose his own path.

“You’ve got to get to know them, and I’ve gotten to know [Mines] really well,” Walker said. “I can tell if somebody is a good person, and he’s a good person.”

These days, an afternoon doesn’t go by without Mines’s cellphone lighting up with someone calling to ask about one of his players. Walker’s presence led sophomores Kiyon Boyd and Derquan Washington to transfer from Dunbar to Woodson this year, and together they have led a six-man rotation that is suddenly the talk of the town.

Walker is the team’s extrovert on the court, known for acrobatic alley-oop dunks and emphatic blocks. He was named the DCIAA player of the year for the second straight year last week when Woodson repeated as league champions. The accolades, combined with an improved jump shot and more playing time on the wing, have Walker’s college options growing.

Almost 15 Division I schools, mostly from mid-major conferences, have offered a scholarship for next year. But teams from the ACC, SEC, Big 12 and Big East have expressed interest if Walker goes to prep school after graduation this spring because he only turned 17 in November.

Walker said he’s not concerned with the uncertainty; his focus is squarely on proving Woodson’s unblemished run this winter is no fluke against a Washington Catholic Athletic Conference powerhouse Thursday. Mines, however, wonders what might come next for his once-overlooked star player.

“He’s still in awe, and he’s still learning new tricks every day,” Mines said. “But conceivably, the kid could be a pro in four or five years.”