NEW YORK -- Aryna Sabalenka broke through with her first major title at the Australian Open back in January, but there’s an elephant lurking in the Grand Slam room: Sabalenka has lost the other five major semifinals in which she’s appeared -- all in three sets. Is this her fragile Achilles heel, her glass ceiling?

An accounting of those defeats: 2021 Wimbledon (Karolina Pliskova), 2021 US Open (Leylah Fernandez), 2022 US Open (Iga Swiatek), 2023 Roland Garros (Karolina Muchova), 2023 Wimbledon (Ons Jabeur). The 25-year-old from Belarus was in position to win all of those matches.

We bring this up because, on the wings of a 6-0, 6-4 victory over Zheng Qinwen of China, Sabalenka is through to her seventh Grand Slam singles semifinal. On Thursday, she’ll play No.17 Madison Keys with a berth in the finals at stake.

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This is the fifth straight major in which Sabalenka has reached the final four, a remarkable achievement for a player that was wildly inconsistent in her earlier years. The subject of semifinals came up Tuesday, when Team Sabalenka spent some time with reporters after she clinched the No.1 Hologic WTA Tour ranking.

“She [talks] a lot about it,” said her coach Anton Dubrov, smiling. “She’s not in the moment during these matches. She’s more thinking too much in front sometimes. She can be in a winning position and she’s thinking about how to finish and not about what she has to do to have control over the match.”

For Team Sabalenka, work doesn't stop at World No.1

Physiotherapist Jason Stacy added, “It’s like she puts more emphasis and pressure on a semi than a final. She gets to a final and she’s like `This is mine. I’m going to take it from you’ kind of attitude when it’s a final.

“It’s almost like [semifinals are] a bigger step for her. When she gets [to the final], she’s like, `OK, I made it, I’m here.’ ”

Will Sabalenka make that second-to-last step on Thursday?

Here’s a breakdown of the semifinals in the season’s last major. Play begins begin on Thursday at 7:00 p.m.

Semifinal 1: No.6 Coco Gauff vs. No.10 Karolina Muchova

How they got here: Gauff sprints past Ostapenko | Muchova dominates Cirstea

This actually happened 18 days ago in Cincinnati, when Gauff came away a 6-3, 6-4 winner in the final.

“A big one,” Gauff said afterward. “Karolina, she’s not an easy player. It’s really good to see her back at the top. I think she's one of the most talented players on tour.”

Read: Why Coco Gauff is having the time of her life at the US Open

It’s the only precedent we have for this compelling matchup.

Five best points from Gauff's win vs. Muchova in Cincinnati final

Gauff, a 6-0, 6-2 winner over Jelena Ostapenko, has won 10 straight matches. Meanwhile, Muchova defeated No.30 Sorana Cirstea 6-0, 6-3 -- saving 10 of 11 break points in the process.

“Mental strength ... how would I describe it?” Muchova asked. “I always feel that I’m a pretty tough cookie in life. That helps with tennis. But yeah, some days are better; some days not.

The key for Muchova?

"I don’t really want to say all the keys with the tactics," Muchova said. "So I’ll just focus on myself. She’s very athletic. She never gives up. Runs for every ball. Doesn’t do many mistakes. She has all the strokes."

These two share another distinction: They both lost to World No.1 Iga Swiatek in the French Open final, Muchova this year and Gauff in 2022. What did the 19-year-old American learn from that all-too-brief match?

“There’s still a lot of tennis left to play,” Gauff said. “I’m still in the mindset that I’m in the beginning of the tournament. Before I would think close to the end, but right now I have the mentality that I told myself I still have another two weeks to play.

“Right now I feel emotionally fresh, which I think was the problem in the past in Grand Slams. I would emotionally be drained.”

Head-to-head: 1-0, Gauff, when she won that Cincinnati final.

Semifinal 2: No.2 Aryna Sabalenka vs. No.17 Madison Keys

How they got here: Sabalenka blows past Zheng | Keys ousts Vondrousova

Sabalenka is now 7-0 in major quarterfinals, 3-0 at the US Open. She’s also the first woman to reach the semifinals at all four Grand Slams in a year since Serena Williams in 2016. But while Serena only took the Wimbledon title that year; Sabalenka has a chance to win two majors.

Sabalenka made it clear in an ESPN interview that she’d prefer to play Vondrousova in the semifinals, avoiding Keys and the pro-American crowd that would support her.

“But I mean, if they’re going to cheer for me more than for her, I’ll be really appreciating,” she told reporters later. “Thank you.”

Read: 'I want a battle for this' - Sabalenka embracing No.1 challenge

This was the first time in 15 majors that all eight of the quarterfinalists were seeded. However, Sabalenka was the only Top 5 seed to get there. Against Zheng, she served phenomenally well, going the entire match without facing a break point.

Sabalenka will try to forget her past two major semifinals. At Roland Garros, she was up a set and had Muchova in a 2-5, 30-40 hole -- and lost. At Wimbledon, she won a first-set tiebreaker but saw Ons Jabeur come all the way back.

“I had a couple of really tough losses this year,” Sabalenka said. “But as I said, we’re not losing, we’re learning. I’m just getting more experience and getting stronger.”

Meanwhile, Keys was a 6-1, 6-4 winner over No.9 Marketa Vondrousova. It was her 26th career victory over a Top 10 player and her second straight, following the fourth-round win over No.3 Jessica Pegula.

Keys, who joins fellow American Gauff in the semifinals, is now 3-0 in US Open quarterfinals -- 6-4 overall. This is the 28-year-old’s first semifinal at the Billie Jean King National Tennis Center since 2018, when she lost to eventual champion Naomi Osaka.

"I feel like you don't know where she's gonna play," Vondrousova said, discussing Keys' devasting forehand. "She can play line, she can play cross. I feel like today she just played great on both sides. She was playing also great the forehand when she was running around the court, so that was very tough."

A win over Sabalenka would give her a chance to be the first American woman to reach the US Open since Serena Williams in 2019. That is, unless Gauff beats her there first.

Head-to-head: Sabalenka leads 2-1, winning their last match in straight sets at Wimbledon this summer.