Leon Vessels hits a return in his Citi Open qualifying match Saturday at Rock Creek Park Tennis Center. (Kelyn Soong/For the Washington Post)

Leon Vessels arrived at Rock Creek Park Tennis Center on Friday afternoon ready to begin his eighth year as a member of the Citi Open tournament operations crew. An occasional hitting partner for the pro players, he had just wrapped up a practice session on center court with Kristina Mladenovic, a French player ranked 34th on the women’s tour, when tournament director Jeff Newman approached him with some exciting news.

Less than 24 hours later, the 28-year-old Washington native would be playing in his first ATP event after receiving a surprise wild-card berth in the Citi Open qualifying tournament.

“I was [like] a big kid on Christmas, man,” Vessels said of his reaction. “You’re just like, ‘Really?’ They told me it was a possibility, but I didn’t find out until last night for sure.”

As a member of the tournament operations crew, Vessels is tasked with ensuring the courts have everything the players need — bananas, sports drinks, water, towels, tissues, bandages, even candy bars and soda. For one week each summer in Northwest Washington, then, Vessels is typically one of the people who keeps the tournament running smoothly.

But on Saturday morning under the scorching sun, Vessels became one of the competitors. He lost, 6-1, 6-1, to 266th-ranked Ernesto Escobedo of California but displayed the confidence and skill that has helped him become a go-to hitting partner for pros.

“To be honest, I look at these courts as my courts,” said Vessels, who grew up four blocks from the tennis center. “If I played [Novak] Djokovic . . . I would try my hardest to get one game. I would give it all I have. It don’t matter who it is, No. 1 or No. 1,000.”

Vessels started playing tennis at age 5 and joined the Washington Tennis & Education Foundation, the beneficiary of the Citi Open, one year later. Vessels received a partial scholarship to play tennis at DeMatha Catholic in Hyattsville, where he peaked as the No. 2 singles player his senior year in 2005 and was named an All-Met honorable mention.

At the Citi Open, he had previously stayed behind the scenes, helping warm up players such as Kei Nishikori, Gael Monfils, Sloane Stephens, Tomas Berdych and Alexandr Dolgopolov, who hit with Vessels nearly every day en route to his Citi Open title in 2012.

Vessels now lives in Los Angeles and works at Santa Monica Tennis Center as a coach. He said he plans on using his Citi Open experience as a “stepping stone” to further his professional career.

But first, his focus will be on the operations crew. He returned to duty just two hours after his match.

“If there’s matches on,” Vessels said, “I’ll be out there helping out.”

Top players withdraw

Three-time Citi Open champion Juan Martin del Potro announced that he has withdrawn from the tournament to continue rehabbing his wrist.

Tomas Berdych, a Wimbledon semifinalist earlier this month, withdrew because of fatigue, while Nick Kyrgios cited a hip injury for his own withdrawal.

The top American men’s doubles team of Bob Bryan and Mike Bryan also pulled out.