PARIS — For almost two hours, Serena Williams and Garbine Muguruza hammered balls back and forth over the net, each one answering the other's power with power of her own, until the final point.
Williams had fired a backhand down the line, directly in front of Billie Jean King, who was watching from the front row. Then she forced Muguruza deep into the other corner.
Muguruza saw Williams lurking at the net, after all the grunting and power tennis, the quick rallies and go-for-broke shots, and she suddenly changed course. Backed into a defensive corner, she lifted a gentle, arching topspin lob that curled into the sky and fell back to the red clay inside the baseline for match point.
At first there was no call from the lineswoman or the chair umpire. The moment for which Muguruza had been waiting most of her life was stalled because of a strange delay.
"I was like, 'Did I win Roland Garros? What happened?' " Muguruza said.
It was Williams who broke the news. She paused for a moment, processed that the ball was in, then graciously lifted her left hand to her racket face and clapped in appreciation of a good shot and a great victory.
Muguruza had just won the French Open 7-5, 6-4 Saturday for her first major title at age 22.
"I can't explain with words what this day means to me," said Muguruza, the first Spanish woman to win a Grand Slam title since Arantxa Sanchez-Vicario won the French Open in 1998.
Muguruza is the third woman from Spain to win a Grand Slam, also joining Conchita Martinez.
Muguruza, seeded fourth, accepted the trophy from King, the 1972 French Open champion and winner of 12 major tournaments overall. For King, it was not merely a compelling match between elite athletes, it was the first glimpse of a new era.
"It's the changing of the guard," King said. "It's starting. This kid has got it all."
Williams, 34, will probably have more to say about that in the coming months, and perhaps years. But it has been a challenging 11-month toil for her. She has gone 0-for-3 in attempts to win a 22nd major title, a mark that would draw her even with Steffi Graf for the Open era (since 1968) record. Margaret Court won 24, but 13 were before the Open era.
Williams beat Muguruza in straight sets at last year's Wimbledon to win her 21st major title. But then she lost at the U.S. Open, at the Australian Open and now at the French Open.
Williams, the top seed and defending champion, dismissed the idea that her pursuit of Graf affected her play. She noted that in Australia, Angelique Kerber played a flawless final and that Muguruza was simply too good for her Saturday.
"Garbine played unbelievable," Williams said. "The only thing I can do is just keep trying."
In her two matches before the final, Williams had looked sluggish, especially in her movement on the court, and she acknowledged playing with a strained upper-leg adductor muscle. Her coach, Patrick Mouratoglou, said there was no injury, but either way, Williams refused to use it as an excuse.
"It was okay," she said. "I'm not one to ever make excuses and say, like, 'Oh, my adductor was hurting' or whatever. I think at the end of the day, I didn't play the game I needed to play to win, and she did."
Muguruza is similar to Williams in some ways. She has a power game and likes to dictate play with aggressive shots. Muguruza often says that she will win or lose a match according to how she strikes the ball, not how her opponent plays. Williams says much the same thing.
Muguruza also displayed impressive mental toughness. At Wimbledon last year she acknowledged having had a case of nerves in the final against Williams, but Saturday she shoved them aside.
With Williams serving at 3-5 in the second set, Muguruza had four match points in a five-deuce game, and Williams saved them all and held serve. Muguruza came back and served out the set without dropping a point, culminating in her graceful lob.
"It was very difficult to see you have four match points and doesn't go your way," Muguruza said. "But it's a final. There's no room for being disappointed or for excuses.
"I still had another chance serving, and I just tried to be calm even though inside, I was like, 'There's no way.' I managed to be calm and just think about what I have to do every point and didn't think about match point or championship point."
Muguruza's tournament started inauspiciously, with a loss to Anna Karolina Schmiedlova in the first set of her first match. That was the only set she lost; she followed that by winning the subsequent 14 sets.
Muguruza is the second woman in the Open era to drop the first set of her first match at a major and then win each subsequent set en route to the title. The other is Francesca Schiavone in 2010 at the French Open.
"I have grown up playing on clay," Muguruza said, "so for Spain, and for me, this is amazing."