If you want to beat Serena Williams, you have to outrun her as she hustles toward all-time greatness, and that’s what Simona Halep did Saturday. She chased down one more ball on every important rally, covered Wimbledon’s Centre Court so quickly that she made the 37-year-old Williams look as if she’s finally slowing down. It’s a race now for Williams against the larger opponents of time, history and opportunity, and Halep just sped up the clock on her.

No matter how many asterisks there are next to Margaret Court’s wooden-era Grand Slam singles record, the number 24 clearly matters to Williams. Maybe too much. How can a player who already has won everything still want one more so badly? “I’m trying to figure out why do I still have pressure, you know,” Williams said this past week.

That was the fascinating question that underpinned the Wimbledon women’s final. How could a player of Williams’s stature and accomplishments, winner of 23 modern major championships and more than $90 million in prize money, need another victory so much that it all but froze her? She came out flat and uptight, heavy-footed, knotted up and short-stroking compared with the magnificent corner-to-corner running of Halep, who has 10 fewer years in her legs.

You knew it was likely to be a defeat for Williams as soon as she fell behind 0-3 in the opening set, spraying nine unforced errors before she hit a single winner. “Aye-yi-yi,” she moaned audibly after she slapped another shot long, on her way to the 6-2, 6-2 defeat.

So she will go back to the drawing board one more time and try to figure out just what she has to do to win No. 24, with a baby on her hip, on tweaky knees and with other nagging ailments, opponents such as Halep growing bolder and better and the pressure increasing every time she puts herself on the spot in another final.

Here is a fact: Only three women have won Grand Slam titles after becoming mothers — Court, Evonne Goolagong and Kim Clijsters. Williams is trying to do something more. She’s trying to prove that a toiling, multitasking mother can surpass the record at 37 years old. “I’m kind of the vintage generation that’s turning to dust,” she joked about her age last week.

Her daughter is almost 2, and Williams is still trying to play herself back into her pre-pregnancy condition, learn how to balance training and motherhood and marshal what physical resources she has left. She talked Saturday about playing more, rather than less, as she heads into the final phase of this season.

“I feel like I’m still incredibly competitive or else I wouldn’t really be out here,” she said. “Today nothing really helped. But also I made way too many errors for a lot of stuff to work. I need to keep working and maybe be able to play some tournaments uninjured, like I did with this one.”

But she also has to worry about overtraining. “I think there’s a limit,” she admitted. “I think if I overdo it, then that could also be a problem, as well.”

Somewhere along the line in the past few years, Williams became a player of directed purpose with her eye on the record book. But she wasn’t always numbers-conscious in her career, and if she fails to equal Court’s mark, it will be because she squandered some seasons. It’s one of the strange wrinkles in her record that from 1999 to 2006 she was great without being unduly dedicated: Although she won eight majors, she went through long stretches of dormancy. There were years she didn’t even enter all four Grand Slam events.

But then the numbers game caught her attention — 15 of her 23 major titles have come since 2007. By 2012 she and her coach, Patrick Mouratoglou, were unabashedly chasing the all-time benchmarks.

The first goal was to reach Chris Evert and Martina Navratilova’s achievement of 18 Grand Slam titles each. Then she approached Steffi Graf’s 22, the modern-era record.

“Okay,” she said to Mouratoglou, “so you told me to beat Evert and Navratilova, then Steffi Graf, so what’s after that?”

“Beat Graf, and then we’ll talk,” he replied.

For Williams to equal the Court record now, a lot of dials will have to line up right, and she knows it. She acknowledges that she doesn’t have another five or even three years, “no matter which way you look at it.”

If she doesn’t do it at the U.S. Open next month, it will only get more unlikely. She has to hope that between now and late August she can somehow recondition and recover some of her pre-motherhood court speed.

She also has to hope that she gets the right draw. Williams, who turns 38 in late September, has made three Grand Slam finals with the Court record at stake and each time has met a player who had the match of her life. It’s a fact she accepts philosophically. “You just have to understand it was their day,” she said. But her day is not quite done yet.

For more by Sally Jenkins, visit washingtonpost.com/jenkins.

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