You know a player is in trouble when her coach struggles to think of anything she can do to get back into a match.

Down 1-4 in the first set of The Western & Southern Open final after less than 20 minutes on Sunday, Simona Halep called Darren Cahill to the court. How could she cool off her red-hot opponent, Garbiñe Muguruza? Cahill talked about trying to “open up the court,” before finally admitting that Muguruza was going to be a tough out today. There’s no way around it, Cahill said, “She’s playing well.”

That’s about all anyone who has to face Muguruza can say at the moment. The 23-year-old Spanish woman has won two major titles, but she may never have played better, more intelligent, more consistent, more resilient tennis than she did this week in Cinicnnati.

After saving three match points against Madison Keys and out-grinding Svetlana Kuznetsova in a marathon, everything clicked for her. On Saturday, Muguruza beat the WTA No. 1, Karolina Pliskova, 6-3, 6-2; on Sunday she blitzed the tour’s No. 2, Halep, 6-1, 6-0. In both matches, but especially against Halep, she played with an ideal mix of aggression and conservatism. She hit with pace and depth, but she rarely flirted with the lines or went for outright winners. On Halep’s serve, Muguruza started points by going deep and down the middle, and then methodically moved her from one side to the other. In Muguruza’s mind, it was a matter of playing offense so she didn’t have to play defense.

“I wanted to step up,” Muguruza said, “because if she steps forward, I’m going to be running a lot.

“I wanted to protect my baseline and keep the other one a little bit on defense.”

Halep was left with few options—defend and she would be pushed around; attack and she would have to go toe to toe with a more powerful player. It didn’t help that Halep’s best offensive option, her forehand, wasn’t firing today. Down a set and 0-3 in the second, she finally dug into a game and reached break point, only to squander her chances with routine forehand errors. After the last one, Halep slapped the court angrily with her racquet.

With a win today, Halep would have reached No. 1 in the world for the first time, but that dream will have to be deferred for now. More concerning is the fact that she (a) lost another late-tournament match, and (b) was blown out for the second straight week. This time, though, while she was overmatched, she did at least keep trying to find a way back in, until she was down 0-4 in the second. Halep’s forehand will be better, but the question remains how she can fend off bigger hitters when they’re on their games. For today, all Halep could do was tip her visor to Muguruza. “I played so bad,” she said with a smile to Muguruza, “and you played so good.”

Halep sounded a little surprised by just how well Muguruza played, and that she never let her level drop. And she’s right, Muguruza’s week in Cincy has been a surprise. We knew she could win majors; what we didn’t know, frankly, is if she could win anything else. This is her first title at a non-Slam event since she won in Beijing in 2015. Last year Muguruza won the French Open and failed to reach another final. Determined to avoid a similar hangover after her Wimbledon win, she came to the U.S. a week early in Stanford, and by this week she was fully acclimated to all the conditions—sun, wind, heat, humidity—that come with playing summer tennis in the States.

And then, just as she had at Wimbledon, when the matches got bigger, she got better.

“I’m happy to be there,” Muguruza said when she was asked what she likes about the important moments. “I’m happy to be in that situation, the tension, being nervous. When I was a little girl, I was always dreaming to be there.”

“It’s me,” is how she summed up what she feels on court in finals these days. That’s what embracing the moment is all about. We wondered who, if anyone, would make the most of Serena Williams’ absence, and it has obviously been Muguruza.

Is she ready for an even bigger stage in New York next week? Muguruza, who has never been past the second round at the Open, was quick to downplay any talk of her being the favorite at Flushing Meadows.

“It’s completely different, the US Open, a Grand Slam,” she said. “Nobody has to believe because you won the last tournament, you’re going to go there and win. There’s lots of times when it doesn’t happen.”

Nobody knows that better than Muguruza, who won her last major after having not won any tournaments at all for 13 months. But there’s no getting around it. She’s the favorite for the Open, and someone, whether it's Halep or Cahill or someone else, is going to have to figure out a new way to beat her.