Jessica Pegula is in the final of the US Open after beating Karolina Muchova

NEW YORK — An American will feature in both finals of this weekend's U.S. Open after Jessica Pegula fought back to defeat Karolina Muchova 1-6, 6-4, 6-2.

Trailing by a set and a break, the idea of ​​Pegula extending her home women's chances seemed illusory, but she showed great courage and turned the game around against an opponent who eventually ran out of steam. Muchova had only recently returned from a nearly 10-month break with a wrist injury and had suffered stomach problems during her win over Beatriz Haddad Maia in the previous round.

On Saturday, Pegula will face No. 2 seed Aryna Sabalenka, who defeated fellow American semifinalist Emma Navarro the night before. With either Frances Tiafoe or Taylor Fritz competing in Sunday's men's final, it promises to be a great weekend for American tennis and an opportunity for Pegula to fulfill a lifelong dream at age 30.

By the end of the match, she was able to smile in disbelief at the prospect, but the scenes of celebration after the final point seemed far away at first. During the early encounters, a somber atmosphere prevailed at Arthur Ashe Stadium. Many of the fans in attendance were probably recovering from the excitement at the end of Sabalenka's victory over Navarro in the first semifinal, and the more subdued atmosphere suited Muchova better than Pegula.

The Czech was able to perform her unparalleled variety without having to worry about external factors, and Pegula also looked sluggish, perhaps feeling the effects of her victory over Iga Swiatek 24 hours earlier.

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After fending off three break points in the third game, Muchova took the first set, thanks in large part to her devastating volleys, which players on the WTA Tour rarely struggle with. As well as the slice, which Muchova used with similar success. As she darted down the baseline, Pegula inevitably had to hit up the court, and there was Muchova waiting, ready to smack away a volley.

To underline the contrast between the two players, Pegula tried a similar tactic afterward. Only she hit her volley from an awkward position and the ball landed in the bottom of the net, giving Muchova a 5-1 lead. Five points later, the set was decided in less than 30 minutes. “She made me look like a novice, I was about to burst into tears,” Pegula said on court after her victory.

Karolina Muchova defeated Jessica Pegula in the first set. (Charly Triballeau / AFP via Getty Images)

Pegula must have feared this. When she is confident, Muchova enters a kind of flow state in which everything looks effortless. Encouraged by a decisive lead, she can play through her entire repertoire of shots. A drop ball helped her break in the first game of the second set, and she hopped onto her chair at the change of ends.

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Pegula continued to drag herself along. Things were starting to get uncomfortable. Her win against Swiatek was her first Grand Slam quarterfinal win in her seventh attempt, but the training didn't feel like much of a reward.

Even when Muchova missed a shot, she seemed excited to try again on the next point, like an inventor who is constantly coming up with new ideas. She looked like she was taking batting practice; Pegula looked like she was in a nightmare.

Jessica Pegula struggled to get into the match until the fourth game of the second set. (Scott Wenig / Associated Press)

The No. 6 seed desperately needed a moment to get herself and the crowd in the mood. This came in the third game of the set when she went for a forehand slice on a break point and used it so well that her opponent landed a missed volley.

“That was luck,” she said afterwards.

Pegula then held on for 2-1 and broke Muchova's serve for the first time in the next game. He defended well again and finally had some joy when the Czech was at the net.

In the next game, Muchova managed another break point and Pegula, thanks mainly to her willpower, won three games in a row to take a 3-2 lead.

Whether Muchova was upset about missing a volley to make it 3-0 or suffering from a lack of match fitness so soon after her wrist surgery, her level dropped while Pegula raised hers. Pegula broke again, thanks to a brilliant inside-in forehand winner and then a clean shot on the backhand side. She also got much better depth on her lobs, forcing Muchova to hit increasingly difficult smashes. In the next game, Pegula even sent a ball cleanly over Muchova's head and into the baseline.

Muchova won seven out of seven points at the net in the first set; in the second set, this ratio decreased to 11 out of 19.

Although Pegula was immediately hit back, Muchova lost her rhythm. She couldn't get going, her shots suddenly weren't quite as natural. Pegula sensed this and began to give in on her returns. After a double fault at 5-4 and a set point behind, Muchova immediately left the court. It was the first set she had lost in the entire tournament.

The early signs in the third set were not encouraging for her. Muchova was throwing forehands and it felt like Pegula was losing the match. She held serve, took the lead for the first time in the match and broke for 2-0. Muchova, perhaps worried about Pegula's improved defense, perhaps feeling physically unable to do so, fired fewer balls at the net. This was good news for the American, who saved a break point and led 3-0.

Jessica Pegula turned what seemed like a lost match when Karolina Muchova's level dropped. (Sarah Stier / Getty Images)

Muchova could have given up at that point, but showed an impressive determination to keep fighting. Trailing 3-1 and 40-30, she delivered two of the most amazing defensive points ever seen on this court. The second ended with a one-handed backhand pass that set up a breakback point. But when Pegula fended it off, it felt like a key battle had been won.

The same was true of the American's next match, which she won at the sixth attempt after a series of thrilling exchanges. The crowd was now fully involved, roaring its cheers as Pegula continued with a final match. Muchova, meanwhile, showed that she even lets out her frustration artistically, throwing her racket high into the New York night and catching it like a circus performer.

Two tiring errors from Muchova, a missed overhead shot and another slice – the hallmarks of her thrilling first set – signaled the beginning of the end. At 0-40, Muchova won a point with a second serve, but another slice missed and Pegula's arms were raised in the air.

After breaking through her personal quarter-final hurdle on Wednesday evening, a possible place in history awaits her on Saturday.

(Top photo: Luke Hales /Getty Images)