RIYADH, Saudi Arabia — While the first six singles qualifiers for the WTA Finals were basking in the glory of more than a week off, Elena Rybakina was grinding in Ningbo, China.

Playing with a sense of urgency and absolutely no margin for error, she won all four of her matches there, the title and a crucial 500 ranking points. Then she jumped on a plane and flew 1,000-plus miles to Tokyo, Japan. Rybakina won her first match, then saved a set point and defeated Victoria Mboko in the quarterfinals. That guaranteed her spot at the year-end championships for the third straight season.

Last Friday, after a debilitating 5,000-mile flight to Riyadh, Rybakina met the press. After four events and 11 matches in a span of 29 days, she sounded weary.

“It wasn’t an easy trip, that’s for sure,” Rybakina said. “A bit of jet lag. I had couple days off. I would say, of course, not the freshest, but I think when the competition starts, it doesn’t matter, you try to do your best. 

“Yeah, we will see what’s going to happen.”

What’s happening, oddly enough, is Rybakina. With impressive wins over No. 2-seeded Iga Swiatek and No. 4 Amanda Anisimova, Rybakina — the last to qualify for the WTA Finals, became the first to advance to the semifinals.

That’s not as incongruous as it might initially seem. Actually, the two are intimately connected by a single word: momentum.

The winning streak is up to nine after the 2022 Wimbledon champion dispatched alternate Ekaterina Alexandrova  6-4, 6-4 in a Wednesday match that had no qualifying implications.

It’s been a strangely uneven season for the 26-year-old who represents Kazakhstan. This was the first time in four years she didn’t reach a Grand Slam or WTA 1000 event final. On the other hand, she’s the only woman this year to accumulate double-digit match-wins at the Grand Slams, WTA 1000s and WTA 500s.

“It was a lot of ups and downs throughout the year,” Rybakina said, “but we were trying to improve, even if it’s end of the season. I’m sure if I do well this week, it’s going to be great.”

Riding the wave

Although you can’t see it, momentum is a fundamental concept in physics. The formula:

p = m × v

Momentum (p) is the product of an object’s mass (m) and its velocity (v). The number helps us understand how objects move and interact with each other, especially in scenarios featuring collisions, explosions and other dynamic interactions.

With this late-season surge, Rybakina consistently has been getting the better of her colleagues in a series of dynamic interactions. She’s peaking at precisely the right time. They say that life is all about timing. It’s similar to teams that idle along through the regular season, barely make the playoffs — then catch fire and go on to win the title.

After losing to Marketa Vondrousova in the fourth round of the US Open, Rybakina found herself last in a three-player race for the last two qualifying spots. Mirra Andreeva, the teenager who won back-to-back WTA 1000s in Dubai and Indian Wells, was in the best shape, ahead of Jasmine Paolini and Rybakina.

After indifferent results in Beijing and Wuhan, Rybakina came to Ningbo as the No. 3 seed — behind No. 1 Andreeva and No. 2 Paolini. But Andreeva lost to Zhu Lin in her first match and Rybakina dropped a 6-3, 6-2 decision on Paolini in the semifinals.

When Andreeva reportedly couldn’t secure a visa in time to play Tokyo, Paolini qualified and Rybakina won those two matches to join her in Riyadh.

Last year, Coco Gauff won nine of 10 matches in Beijing and Wuhan, then took the title in Riyadh by winning four of five, including a spectacular final over Zheng Qinwen.

Three years ago in Fort Worth, Caroline Garcia rode a hot streak to the WTA Finals championship match, where she bested Aryna Sabalenka. Garcia was ranked No. 35 going into Cincinnati but rallied to qualify and, eventually, won the title. A run to the US Open semifinals gave her 13 wins in 14 matches, the streak that eventually landed her in Texas. 

Another way to define momentum — confidence.

In 2016, Angelique Kerber rode that wave for nearly the entire season. After reaching the final in Brisbane, she won the Australian Open. Later, she got to the Wimbledon final, took the title in Cincinnati, reached the gold-medal match in Rio de Janeiro and won the US Open.

“It’s tough to explain the feeling in words,” said Kerber on Tuesday, sitting in Riyadh’s player lounge. “You have that momentum and you try to take it as long as possible. You are staying in the moment. You are in such a zone. There’s no Plan B, and in your mind, there’s no chance that you lose a match.

“Rybakina, she’s got nothing to lose. We know that when she’s hitting the ball good, she serves well, there’s not a lot of players that can beat her. So the momentum is now, she’s into the semis, let’s see what she can do.”

Confidence is contagious

After a straight-sets win over Anisimova, Rybakina encountered a stubborn Swiatek in her second round-robin match. She had lost all four of this year’s matches to the 24-year-old from Poland (and eight of nine sets) and seemed out of sorts. Swiatek went on to win the first set.

And then Rybakina won 12 of the next 13 games.

“Very pleased with my serve, and I think the return also got better throughout the match,” Rybakina said afterward. “Definitely the serve is a big advantage for me, and whenever it works, I have chances to win against anyone.

“So hopefully I can continue like this, since it’s my big weapon in the game.”

The serve is Rybakina’s signature stroke. She leads all Hologic WTA Tour players with 480 — more than 100 ahead of Linda Noskova — which works out to 6.5 per match. And this indoor venue amplifies that shot.

Going forward, she’ll need it. In two previous appearances at the WTA Finals, Rybakina (2-4) never advanced past the group stage. This one feels different.

“When I came to Asia, I knew of course there is still a lot of players who can qualify,” Rybakina said. “I tried to do my best. I played against tough opponents, the ones I lost before. I’m pretty glad that last few weeks went successful for me.”

Ons Jabeur knows what she’s feeling. In 2022, she got hot on the spring clay, reaching the Charleston final, winning the title in Madrid and making another final in Rome. After winning the title on the grass in Berlin, Jabeur’s 11th straight match-win delivered her to the final — where she lost in three sets to Rybakina.

“Winning gives you confidence, with confidence you dare to do more things on the court,” Jabeur explained. “I have great memories from 2022. Yes, I was feeling so tired, but I was enjoying being tired.”

Jabeur, who said she hasn’t picked up a racquet in the four months since Wimbledon, is taking a break from tennis but hopes to return. She’s been closely following Rybakina’s run in Riyadh.

“Usually, the one who plays good at the end of the season plays better at the WTA Finals,” Jabeur said. “I’ve seen the results before, and that’s how it happens. I’m sure she’s confident and I think she likes to play here on these courts. 

“So there’s a pretty good chance that she could win here.”