Aryna Sabalenka was once so unpredictable, so volatile, that sometimes it was hard to watch her play tennis. 

She hit the ball harder than anyone in the women’s game, but an emotional meltdown seemed to be only a point or two away. The pressure of living up to her prodigious talent seemed like a burden she couldn’t escape. At one point just a couple of years ago, Sabalenka even went through a period of months where she had the serve yips so bad that she resorted to an underarm delivery. 

Now look at her. 

Not only is she a three-time Grand Slam champion after winning the US Open on Saturday, beating Jessica Pegula 7-5, 7-5, but she’s now the most bankable player in women's tennis. 

And all things considered, she’s probably the best. 

At 26 years old, Sabalenka’s US Open triumph seems like a long time coming after two gut-wrenching semifinal losses and last year’s final collapse against Coco Gauff. But it’s also a testament to a fascinating athlete who has evolved into something that might surprise even some of her biggest supporters. 

She’s not only the most consistent performer in women’s tennis now, she’s arguably the toughest and most clutch under pressure — just a few years after corralling her emotions and erratic streaks in these big matches seemed like a lost cause.

“I'm super proud of myself,” she said during the on-court trophy ceremony. “I never say that, but I'm super proud of myself.”

She should be. 

Among the active players in women's tennis, Iga Swiatek has five Grand Slam titles and the No. 1 ranking, Naomi Osaka has four majors but question marks about whether she can get back to that level, and now Sabalenka is right on their heels with three. 

But in the most important matches, and at every Grand Slam except the French Open, there’s no doubt anymore about who should be favored to win the tournament. 

In the last eight Slams she's played, Sabalenka has won three (two Australians, one US) with one finals loss, three semifinal losses and one quarterfinal appearance. 

That’s just remarkable consistency and excellence on all surfaces even compared to Swiatek, who has won two of her last eight Grand Slams (both on clay) with two quarterfinal losses, two fourth-round losses and two third-round losses. 

Whereas Swiatek seems now to play with such heaviness and anxiety in the biggest tournaments, Sabalenka has broken through the mental barriers that once seemed like a forever curse. 

Just a few years ago, this would have been inconceivable. 

From the moment she arrived as a top player, Sabalenka’s strengths and weaknesses were pretty well-defined. She could hit the absolute cover off the ball, a rare player in women’s tennis whose ground stroke power was essentially on par with the men. You could — and still can — feel and hear how much effort and muscle she puts into every stroke. 

When she was on, she was really on.

But the downside for Sabalenka was considerable. There was never really a Plan B, and as the pressure went up deep into a tournament, her game became less reliable. When those big cuts at the ball started missing, it was a quick spiral into disaster. 

In 2021, Sabalenka made her first Slam semifinal at Wimbledon and was about as un-clutch as a player could be, losing to Karolina Pliskova 6-4 in the third set. Then just a couple of months later, Sabalenka was the clear favorite to win the US Open title but imploded in the third set of the semifinals against unseeded upstart Leylah Fernandez.

To her great credit, though, Sabalenka owned it. After a flurry of errors handed Fernandez a spot in the finals, she came in the press room and explained it very simply: “This is what we call pressure. That’s why I'm a little bit disappointed about this match because I had a lot of opportunities and didn't use it. Well, this is life. If you’re not using your opportunities, someone else will. I will try to improve it. I will keep working and fighting, and I believe that one day it will come.”

Sabalenka has had to absorb a few more gut punches along the way, but it has indeed finally come. She’s managed to harness her power and become a more thoughtful and strategic player while maintaining her trademark aggressiveness. More impressively, she’s figured out how to get comfortable being uncomfortable in the heat of a battle when things aren't always going her way.

In Saturday’s final, Sabalenka was clearly the player dictating more of the points. But Pegula managed to hang around and scrap her way back in the second set to actually grab a 5-4 lead and have a chance to take it the distance. 

It would have been natural for Sabalenka to have flashbacks to last year when Gauff kind of did the same thing, pushed it to a third set, got the crowd involved and flustered Sabalenka to the point where she was mentally out of it.

“The good news is that it's me against me,” Sabalenka said that night after smashing a bag full of rackets back in the locker room. “The bad (news) is that I’m still having these issues playing against myself. But it's OK. I’ll work harder.”

The test for Sabalenka came in that 5-4 game with Pegula serving for the set and all the momentum in her favor. And what did Sabalenka do? She pounded the ball — boom, boom, boom — to get three break points. And then on her third try, Sabalenka once again pushed Pegula around and confidently found the open court for a winner. 

It was the response of a champion, and now women’s tennis has a real problem on its hands. Sabalenka is so much more powerful and aggressive than every other player, she is usually going to be the player who dictates who wins or loses. But now, you can't count on Sabalenka to self-destruct anymore. Swiatek, Gauff and the rest of them are going to have to find a way to take it from her whenever she gets a whiff of a Grand Slam title. 

With a US Open trophy to add to her collection, the dam has officially broken on the Sabalenka onslaught. If she's truly become this much of a mental monster under pressure, Saturday's victory was only the beginning.