Jared Donaldson reacts after losing his first-round match to Rajeev Ram at the Citi Open. (Toni L. Sandys/The Washington Post)

A young Jared Donaldson was repeatedly told he needed to change his grip on the tennis racket. Known for being stubborn, he refused. But after established tennis professionals Justine Henin and Mardy Fish told Donaldson to make the change, doing that became his singular focus.

“When Jared believes something and wants to do it, it becomes part of his game,” said Courtney Donaldson, Jared’s father. “But to get him to change, he’s got to understand it and believe it. His biggest strength can be his biggest weakness.”

From training with Taylor Dent to hitting with Roger Federer, Jared Donaldson is finding his way in tennis by learning to accept guidance from others. Making his ATP Tour main draw debut at this year’s Citi Open at William H.G. FitzGerald Tennis Center in Rock Creek Park, the 17-year-old is using the experience to guide his next steps in the sport.

Donaldson lost his first-round match Monday to Rajeev Ram, 6-7 (7-1), 6-4, 7-5, but said qualifying for his first ATP Tour main draw is something he’ll remember forever.

His youthful exuberance showed throughout the match, as he repeatedly argued with the chair umpire and muttered expletives under his breath in frustration when a point didn’t go his way

“It’s a learning experience, and hopefully I’ll get more experience and more used to the feeling of playing in an ATP” event, Donaldson said. “It was my first round, so hopefully that will come with time.”

Donaldson started working with Dent, a former top-50 singles player, last November. Their main focus was Donaldson’s serve. Dent said there wasn’t anything he liked about it when Donaldson first came to Dent’s academy. His elbow was too high, and his wrist would flop back behind. Dent said the ball toss and the type of spin Donaldson was trying to put on the ball were also wrong.

“We saw a lot of technical issues on the serve,” Dent said. “It’s close to where we want it now. Changing something like that just takes time to get confidence in. In practice, he serves great. During the matches, it comes and goes a little bit. It’s going to come in time. His serve has really turned around a lot.”

After Donaldson established himself as a top junior with a runner-up finish at the 18-year-old national championships in Kalamazoo, Mich., the USTA reached out to him with an opportunity to hit with Federer in Dubai for three weeks. Donaldson said the biggest thing he took from the experience was how to implement what he saw Federer doing on a daily basis into his own practice regimen.

The experience was comparable to when he finally decided to change his grip on the racquet. Dent said he had sensed reluctance from the Donaldsons about the standards he set for Donaldson’s play, but that changed after Donaldson hit with Federer. Dent said getting to hit with the pros at the Citi Open this week will also be a good experience for Donaldson. He’s also playing doubles this week with Stefan Kozlov, their first-round match scheduled to be against 15-time Grand Slam winners Bob and Mike Bryan.

“I felt there was some slight hesitation because I was setting the bar pretty high with what his shots had to do,” Dent said. “It was nice going out to Dubai, and Federer was doing all of the things that I was asking him to do. It was kind of like, ‘That’s what it is, so now we have to get to work and do it.’ It was kind of confirmation that that’s the direction we needed to go.”

The Citi Open main draw is a milestone for Donaldson, one his father hopes is part of an ongoing process for Donaldson to understand what the lifestyle of a professional tennis player is. He has 18 months before he has to decide whether he wants to play collegiately or turn pro. Traveling around the world to compete in various events is something Courtney Donaldson wants his son to be sure he wants.

Jared Donaldson has been traveling since he was 11, living in South America for two years when he was 14 and playing tournaments there. Washington’s tournament is closer to his home in Rhode Island, and he was so excited about his first ATP Tour main draw that he asked Dent to take the red eye from California and watch.

“I try not to get too excited,” Dent said. “I know there’s a long way to go. I have a lot of hope for Jared. I have a lot of optimism for where he can go. There’s a long way to go. There’s a lot of work to do between here and there. This is a big opportunity, but will it be his last big opportunity? No.”