PARIS — Serena Williams was slow to the ball and frequently out of position Saturday on the red clay of Roland Garros, where she has won three French Open championships.

Even her serve, the most feared weapon in women’s tennis, let her down against an unseeded, Russian-born American who was unfazed by the grandeur of 15,000-seat Court Philippe Chatrier and the credentials of her opponent.

With power and fighting spirit to rival that of Williams, 20-year-old Sofia Kenin pulled off a 6-2, 7-5 upset that represented Williams’s earliest ouster from a Grand Slam event in five years. It also stopped short the veteran’s quest for a 24th major singles title that would tie Australia’s Margaret Court for the sport’s record.

Twenty months after giving birth, Williams is far from the peak of her powers. And with tennis academies across Europe and in her own South Florida backyard churning out hard-hitting, steely nerved challengers such as Kenin, who was born three years after Williams turned pro, Williams may never reclaim her place atop the sport.

Sportswriter Liz Clarke analyzes the 2018 U.S. Open women's final controversy, where tennis Serena Williams was fined $17,000 for violations. (Taylor Turner, Melissa Macaya/The Washington Post)

But 20 years after she made a seismic statement at Arthur Ashe Stadium by toppling the ­defending U.S. Open champion and the world’s No. 1 player to win the first of her 23 majors, Williams plays on.

Well after Lindsay Davenport, Martina Hingis, Justine Henin, Kim Clijsters and most of her early rivals retired, Williams battles despite having achieved worldwide fame, staggering wealth, unassailable Hall of Fame credentials and an adoring family with whom to share it.

Williams plays on, at 37, not simply because she believes she has more Grand Slam titles to win. She plays on because she also believes she has more statements to make — statements, at this stage of life, about self-esteem, equity and the unique challenges facing women, women of color and mothers juggling multiple roles and demands.

Williams’s conviction in addressing off-court issues has deepened since the birth of her daughter, Alexis Olympia, in September 2017. Via social media posts, carefully chosen interviews and the HBO documentary “Being Serena,” Williams has spoken frankly about the life-threatening circumstances of her emergency Caesarean section, the challenge of breast feeding and the collision of emotions she wrestled with as a first-time mother returning to work.

In an August 2018 Instagram post, she confessed to feeling that she was “not a good mom” and shared advice she had gotten from her own mother about postpartum depression.

“Most of you moms deal with the same thing,” Williams wrote. “Whether stay-at-home or working, finding that balance with kids is a true art. You are the true heroes. I’m here to say: if you are having a rough day or week — it’s ok — I am, too!!! There’s always tomm!”

Here at the French Open, she created a new medium for the statement she wants to make to women. It was woven, quite literally, in the fabric of her custom-designed tennis outfit: four French words, embedded in the black-and-white, geometric pattern of her zippered cape, fitted crop top and billowy skirt, that proclaimed “Champion,” “Queen,” “Mother” and “Goddess.”

“Those are things that mean a lot to me,” Williams explained, characterizing the words as reminders to herself and to other women of all they are and can be.

The ensemble drew glowing reviews from Vogue’s Christian Allaire, who praised its nontraditional look and the implied rebuke, in championing female empowerment, to the French Tennis Federation’s criticism of the catsuit Williams had worn in the previous year’s tournament, in part, to guard against a recurrence of dangerous blood clots.

“Very clever indeed,” Allaire wrote. “It seemed to say, ‘I’ll take your catsuit bam and raise it.’ ”

To be sure, the outfit is more than athletic wear in the same way that Williams, at this stage of life, is more than an athlete. It is a banner that proclaims that the identify and power of the woman wearing it doesn’t reside in one role but extends to many.

Here in Paris, Williams the tennis champion opened her 2019 French Open campaign amid more drama than usual.

She played just one clay-court match in the run-up, at the Italian Open last month before she withdrew with a left knee injury.

Then, one week before her first-round match, she was photographed in a wheelchair during a family trip to Disneyland Paris. That triggered widespread speculation that she would withdraw from the season’s second major. But she strode on court, without a knee brace, and overcame rust and a rash of errors to dismiss Vitalia Diatchenko, ranked 83rd in the world.

She was more effective in her next match, storming into the third round with a straight-sets victory over Kurumi Nara that included 36 winners and 10 aces. But she clearly lacked the speed and explosiveness that have marked her greatest victories.

Williams provided few details about her knee injury, saying simply: “It’s okay. I’m still here, so it’s doing okay.”

She had even less to say when asked about the circumstances that required a wheelchair. “I’m not going to get into that,” Williams said. “I’m playing, and all’s good.”

On Saturday, Kenin was remorseless in exposing facets of Williams’s game that aren’t up to par, particularly her movement and fitness, blasting passing shots past her and yanking her from side to side.

The 20-year-old also had little trouble with Williams’s vaunted serve, breaking her four times. And the youngster relished the battle, frequently shouting, “Come on!” and drawing the crowd’s disapproval at various points by smacking the net post with her racket, kicking the clay and taking extended, skeptical looks at marks on the court when she felt a linesperson had erred.

“I knew I just had to show the crowd, like, ‘Listen, Sonya Kenin is in the house!’ ” Kenin said, referring to herself by her nickname.

Speaking to reporters before making a hasty exit from the grounds, Williams said she felt “pretty far away” from what she feels is her true ability. But the bright side, she noted, is that any shortcoming is because she hasn’t been able to practice as much as she would have liked. “At least I can start trying to put the time in now,” she added, with the start of Wimbledon looming July 1.

In the view of former pro James Blake, who wrote about the cultural and social impact of Serena and Venus Williams, along with other athlete-activists in his 2017 book, “Ways of Grace,” Williams’s mere presence on court at 37 is impressive.

“You just don’t recover as quickly from injuries or even from taxing workouts or matches [at 37] the way you did when you were in your 20s,” said Blake, who retired from the pro tour at 33.

Parenthood, he noted, adds another challenge.

“Sleep is so important for an athlete, especially an older athlete to aid in recovery,” Blake said. “Every mother knows sleep becomes much more sparse when you have a newborn in the house. Even if you are doing everything possible to shield yourself from that, it will still always be affected in some way.

But it’s Williams’s willingness to speak out on issues beyond sports that impresses Blake most.

“I don’t know if a switch flipped in her when she had Alexis, but she has the voice that can make a huge difference,” he said. “She has opened tons of eyes to the dangers of childbirth and how the numbers are unjustifiably skewed towards being much more dangerous for African American mothers. Speaking out for equality and equal treatment for women and women of color is, sadly, such a pressing issue in 2019. She can speak up and give so many other athletes and non-athletes the courage to speak up, as well, in the face of inequality.”

In terms of a legacy, that can have greater impact than any number of Grand Slam titles.

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