“I think this is one of the best sets of tennis I’ve seen Pliskova play,” Chris Evert said as Karolina Pliskova took a 4-2 lead in the third set over Caroline Wozniacki in Toronto on Friday. It was hard, at that moment, to argue.

Pliskova, the WTA’s current No. 1, had finally found a groove. After suffering through four rain delays and nearly five hours on court, and being forced to hit hundreds of balls by Wozniacki, Pliskova was patiently measuring her shots rather than just slugging the first thing she saw. She had won two of her three previous matches with Wozniacki in 2017, and it looked like, after a topsy-turvy first two sets, she was going to win this one, too. Pliskova was, by all appearances, going to back up her No. 1 ranking.

But that’s the thing about Wozniacki: Whatever else anyone may think, she’s always the last person to believe she’s going to lose. She’s a two-time season-ending No. 1, and while that was six years ago, she still acts and plays like she thinks she should win every match she’s in. And she wins a lot of them for that reason alone. Wozniacki forces her opponents to beat her; her opponents, in turn, know they’re going to have to make their shots, and especially their putaway shots, until the last point is over and match is officially done and dusted. They’re not going to get any help. Pliskova led 5-1 in the first set, but Wozniacki won it 7-5.

That, obviously, can wear on a player’s mind, and it seemed in the end to wear on Pliskova’s. Just when it looked as if she had conquered her inconsistency and asserted her superiority, everything went haywire again for her. Wozniacki kept making shots, kept running down balls, kept “asking the questions,” as the cliché goes, and after two hours and 56 minutes, Pliskova finally ran out of answers. Serving at 4-5 in the third, Pliskova made three quick unforced errors—a backhand long, a forehand long and a forehand into the net—to end the match.

In one sense Wozniacki’s 7-5, 6-7 (3), 6-4 win was a product of her defense and grit, as it always with her; she made just 15 unforced errors in 221 points. But she also showed off a little more offensive oomph—dare we call it firepower?—than usual. Wozniacki out-aced the WTA’s ace machine, eight to five, and her 29 winners was a respectable number for her on a slow hard court like the one in Toronto.

While Pliskova walked away wondering how she lost, Wozniacki flashed the smile of a player who knew that all of her effort and belief down the stretch had paid off. She moves on to the semis, where she’ll play either Lucie Safarova or Sloane Stephens. And with this win, she gives the rest of us a reminder that she’s part of the U.S. Open hunt, too. Wozniacki has been a semifinalist there three times, and a finalist twice. You know she thinks she belongs there again.

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