Garbine Muguruza led Serena Williams 4-3, 15-0 in the first set when she stepped to the middle of Centre Court to hit a forehand. It was the kind of shot that Muguruza had been putting away routinely for the past two weeks, and for the first 30 minutes on Saturday.

The 21-year-old, to the surprise of many – but not to her or her opponent – had come out for her first major final and taken the initiative from the world’s best player. It was the Spaniard, not the American, who was swinging freely and aggressively, and who recorded the first service break. It was the American, not the Spaniard, who was so worried about her opponent’s powerful return of serve that she double-faulted three times in her opening service game.

Now, though, as Muguruza stepped forward for that forehand at 4-3, she could see the outline of the first-set finish line. She may have walked on court expecting to play well against Serena, but winning? That’s another level of belief entirely. Whatever Muguruza thought, she thought it for a split-second too long. She hesitated with her swing; instead of rocketing a winner, she blooped the ball back, well within her opponent’s reach.

That, it turned out, was all Serena needed. At that moment, she was behind the baseline; most other players in that situation would have been happy to put the ball back in the court. But that was never going to be Serena’s way.

This was a chance not just to make a shot, but to send a little piece of information down to the woman at the other end of the court. Serena changed her stance and ripped a forehand crosscourt. Muguruza couldn’t handle the pace, and, it was soon clear, she couldn’t handle the information that Serena was imparting. Muguruza lost that point, her serve, the set, and eight of the next nine games.

With that forehand, “Serena sent a message,” her coach, Patrick Mouratoglou, told ESPN later. “‘Now I’m here.’”

No wonder Muguruza stopped playing so freely and confidently; the simple fact that Serena was “here” meant her chances of winning had plummeted. It wasn’t just that Serena hit with more power than Muguruza. What struck me as I watched Serena stretch her lead wasn’t her superior power, but her superior variety and creativity.

After the opening stretch of games, Serena began to read Muguruza’s serves and returns. She began to anticipate Muguruza’s wide serve to her backhand in the ad court, as well as her backhand return down the line. Once that happened, Muguruza couldn’t find a way to mix things up.

At the same time, Serena found ways to surprise Muguruza as the match went on. She won an important point by sending a second serve down the T in the ad court, where she usually goes wide.

She won another at a crucial stage in the second set when she pulled a backhand crosscourt instead of going down the line and into the open court. Often her response to a well-struck Muguruza ball wasn’t just to get it back over the net but to put it in a difficult spot for her.

Serena has signature shots – the rifle-crack serve, the “get-out-of-here-with-that-nonsense” return – but she doesn’t have signature shots to specific places. She can go down the T or wide with her first serve equally well, and can place her second serve in either corner. On her groundstrokes, she can hit down the line, crosscourt, or at an acute angle with equal effectiveness.

By the middle of the second set, the Serena onslaught had set in, and Muruguza, who would lose 12 straight points from 1-2 to 1-5, couldn’t find an answer.

“When I lost the first set, I was a little bit sad,” Muguruza said, “because I had chances. I just tried to keep going, but she was playing really good – aces, winners, what could I do?”

All Muguruza could do was hang around and hope that Serena would get, as the Spaniard said, “nervee-us.” That’s exactly what happened. Serena, as she had while trying to close out the French Open final, tightened up, and Muguruza was ready for it. In the end, though, she had fallen behind by one game too many.

Serena Williams Final Press Conference

Afterwards, Serena applauded a tearful Muguruza’s efforts, and said she would surely be holding the Wimbledon winner’s plate someday soon. Muguruza appreciated the words, though she didn’t sound completely convinced by them in her press conference later. What she did sound convinced of was her ability to play with the world’s best. “I have a good level,” she said, “I have to believe that. Here I have the proof... I felt free on the court, no fear.”

Twelve months ago, another 21-year-old, Eugenie Bouchard, sat in the same chair after being trounced in the same round by Petra Kvitova. The loss was bad enough that it appears to have left a deep scar in Bouchard’s game; she has rarely been the same player since.

By all appearances, this loss wasn’t a scarring one for Muguruza, who won the crowd, the press, and her opponent over with her easygoing confidence and brave game. I especially liked what she said about the process of being successful.

“I learned that every match is very important,” Muguruza said, when asked what she had discovered during her Wimbledon run. “First rounds are really hard because you are nervous. [But] if you get through all these situations and you’re mentally tough, you have the chance to play this kind of match.”

No one knows more about this process, and getting through these situations, than Serena Williams. According to her, this match was definitely a process, from the practice court to the final game. “In practice, my serve was off,” Serena told ESPN. “I didn’t feel it... But I kept going after it.”

Then, when she finally found it and everything was clicking, she had to stop from getting ahead of herself. “[At 5-1 in the second set] I definitely started thinking, ‘One game, Serena Slam,’” she admitted. “And that’s the wrong way to think.”

But as she has all season, Serena survived her nerves. This time, she did it by being what most tennis players can never be in the middle of a match: Reasonable with herself.

I definitely started thinking, 'One game, Serena Slam,' and that's the wrong way to think
Serena Williams

“[At 5-4], I told myself, ‘worst-case scenario, you’ll be in a third set.''' Serena said. “‘Best-case scenario, you’ll close it out.’ I kind of calmed down after that, and I was able to do better.”

Watching Serena carve up the court and roll towards the title in the second set, I tried to remember her last Serena Slam, in 2003 and 2004. What came immediately to mind was the sight of her doing the same thing – carving up the court with a dazzling variety of angles – to beat her sister Venus in the US Open final.

A lot has changed since then, obviously, for a woman who has survived a pulmonary embolism and the death of a sister. In those days, at 21, with the sport in the palm of her hand, Serena appeared to be fearless. Now no big match of hers is complete without an attack of nerves to fight off. Back then, she has said, she was driven by the thought of getting revenge on an ex-boyfriend. This time she was coaxed and coached the whole way by Mouratoglou, and they shared an open-armed hug when it was all over.

Afterwards, she said that it was the thought of another Serena Slam, of matching her younger self, that drove her the most. “I’ve been trying to win four in a row for 12 years,” Serena said, “and it hasn’t happened. I had a couple of injuries. It’s been an up and down process. I honestly can’t say that last year, or even five years ago, I would have won four in a row.”

While Serena is as far ahead of the WTA field as ever at the moment, she seems to appreciate this Serena Slam, and the difficulty in achieving it, more than the first time around. For all of her experience at 33, nothing can match the brashness of a world-beating athlete at 21.

Serena has spent the past few years racing ahead of the rest of the WTA field. At the US Open next month, she’ll have a chance to catch up to the last great women’s champion, Steffi Graf. But it was easy to understand why, for today, Serena seemed pleased to have caught up to herself.