Sloane Stephens returns a ball during her match against Olga Puchkova in their first-round match at the Citi Open. The 88th-ranked Puchkova upset the second-ranked Stephens in straight sets. (Toni L. Sandys/THE WASHINGTON POST)

Sloane Stephens, the No. 2 seed in the Citi Open and the 15th-ranked player in the world, made an early and ungraceful exit from the William H.G. FitzGerald Tennis Center on Monday night, dropping her first-round match to No. 88 Olga Puchkova, 7-5, 6-3.

Dressed in neon orange from head to toe, Stephens’s sluggish play was glaring from the get-go. The 20-year-old lumbered stiffly around the baseline with her head down between points, body language that indicated to a large but silent crowd that this was a player searching for the game that helped her beat Serena Williams on her way to the semifinals of this year’s Australian Open.

“I just didn’t play that well, wasn’t feeling the ball great,” Stephens said. “I would say that I’m a pretty consistent player — I don’t really hit balls all over the place, that’s not really how I play — but today there were some that I really couldn’t believe it went that far out.”

Stephens smacked several groundstrokes long and lacked precision with her first serve. On the verge of falling down 4-1 in the first set, she let out a prolonged shriek of frustration that broke an already tense silence.

The crowd tried to rally the subdued starlet, and it worked — for a bit. Stephens held serve in dominating fashion then broke Puchkova, but inconsistency struck again as a few unforced errors and that faulty first serve let Puchkova break back.

Mistakes doomed Stephens again in the second. Forehand after forehand flew long as Stephens turned her palms to the sky on more than one occasion, looking uncomfortable both on serve and off. The low point came when, up 40-love and on serve, Stephens let Puchkova come all the way back, eventually allowing her to break with a double fault.

Despite the crowd’s urging, Stephens never recovered, the final score giving an impression of a much closer match than was actually played. Stephens didn’t record a single ace and allowed Puchkova 15 break points.

Stephens, who battled a torn abdominal muscle last year, said she felt fine physically in the loss.

“When I’m injured I play great and when I’m healthy I can’t hit a ball in the court,” she joked.

Stephens has reached the quarterfinals or better in five WTA tournaments she has played this year. Two of those performances came in Grand Slams (Australian Open and Wimbledon). But after her fourth first-match exit in a non-Slam event, she brushed off the notion that she doesn’t bring as much intensity when the spotlight is dimmer.

“Most of the tournaments I train really hard, like leading up to a tournament like this, and I don’t play very well,” Stephens said. “It’s probably because I did fitness like eight hours a day for like the last week. . . .

“People just don’t know that. So you’re like, ‘Wow, you look slow and horrible.’ I’m like, ‘Sorry, just a bad day.’ I don’t know why I play so well at the Slams.”

Del Potro regroups

Juan Martin del Potro will return to competition Wednesday night at the Citi Open, four weeks after wrenching his knee in his epic loss to top-ranked Novak Djokovic in the semifinals at Wimbledon.

Ranked No. 7 in the world, del Potro, 24, is the tournament’s top seed following the withdrawal of Frenchman Jo-Wilfried Tsonga. After a first-round bye, he’ll face either rising American Ryan Harrison, 21, or former world No. 1 Lleyton Hewitt.

Despite the recent heartrending loss to Djokovic, which at 4 hours 43 minutes set a record for a grass-court semifinal, del Potro had no difficulty Monday enumerating the many positives.

“Even in the loss, I played against the No. 1 in the world, on Centre Court of Wimbledon, my first semifinal there,” del Potro said. “Novak is a friend of mine. We were playing that match like it’s a war down there. In the end, we are still friends. We are normal persons, and I think we played a very fair game. In tennis, one has to win, and one has to lose. That day, he beat me. Last year, for the bronze medal of the Olympics, I beat him.

“This is tennis. I say to him, ‘Congratulations.’ I think I am very honest. He deserved to win. At the end of the match, I was tired, and he was ready to take the opportunity.”