MADRID -- The final four are set at the Mutua Madrid Open, where No.1 Iga Swiatek and No.2 Aryna Sabalenka are eyeing a second straight final showdown. 

Sabalenka, champion here in 2021, takes on No.9 Maria Sakkari in the first semifinal on Thursday at 4 p.m. The two familiar rivals are set for their ninth meeting on tour, with Sabalenka leading the head-to-head series 5-3.

Still undefeated on clay this season, Swiatek will headline the night session, where she is set to face No.12 seed Veronika Kudermetova at 9 p.m. Swiatek has won all six sets the two have played, most recently a 6-0, 6-1 victory in the Doha semifinals in February. 

How they got here: Swiatek d. Martic | Sabalenka d. Sherif | Sakkari d. Begu | Kudermetova d. Pegula

Here are four keys for the final four players:

[1] Iga Swiatek: Stay focused

Swiatek extended her win streak to eight matches after easing past Petra Martic to make her fifth straight semifinal and first in Madrid. Losing just three games, her performance was a confident reset after being taken to three sets in a late-night battle with Ekaterina Alexandrova in the fourth round. 

Swiatek has not come close to losing a set to Kudermetova. The set scores in their previous three meetings? 6-3, 6-3, 6-1, 6-0, 6-0, 6-1. None of those came on clay. 

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As she looks to win her first Madrid title to complete her set of the biggest European clay-court tournaments on the calendar -- she has already lifted the trophy twice at the French Open, Rome and Stuttgart -- Swiatek just needs to pull her cap down low and work. Before the tournament, she vowed to take things one match at a time as she continued to pull and process the data points to maximize her game in the unique and relatively unfamiliar conditions at the Caja Magica. 

"Just getting the experience of playing here, it was easier and easier every match to stay disciplined sometimes and make the right decisions," Swiatek said after her quarterfinal win. "Because at the beginning I felt like I had to take care of so much stuff that was a little bit different than in Stuttgart, for example.

"But right now it became more natural, and I can use my intuition a little bit more. That's what I was looking for."

Her learnings will be tested by Kudermetova, who has the same weapons as Alexandrova but with more consistency and experience. If power is the ultimate disruptor of the Swiatek game, Kudermetova can bring it. But Swiatek has proven time and again that she can dig in, withstand that pressure and give as good as she gets. All you have to do is look back 10 days ago to her 6-3, 6-4 win over Sabalenka in the Stuttgart final.

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[2] Aryna Sabalenka: Keep a cool head

Sabalenka may not be the World No.1, but she's spent the 2023 season closing the gap between her and Swiatek, both in points and in perception. 

"She's the one that is playing the best tennis right now, better than anyone else," said Sakkari, her upcoming semifinal opponent. 

Sabalenka continues to strike the ball incredibly well, defend admirably and channel her resilience when under pressure. She's been tested in Madrid, first in a tight two-set match against Camila Osorio in the second round, and in a three-set win over Mayar Sherif in the quarterfinals. 

The key in both matches? Keeping her head on straight.

"I just couldn't adjust for her game, and I was really going crazy," Sabalenka said after her comeback win over Sherif. "I'm really happy that I was able to stop myself, to take a little breath and just start everything from the beginning."

Still the tour leader in wins this season, Sabalenka is bidding to extend her head-to-head record over Sakkari to 6-3 and advance to her tour-leading fifth final of the season.

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[9] Maria Sakkari: Keep her sense of humor

After defeating Irina-Camelia Begu 6-7(3), 6-4, 6-2 in the quarterfinals, Sakkari was asked how it felt to make her 21st semifinal and first in Madrid. 

"Semifinals is my round, eh?" Sakkari said. "It's like me winning a tournament. It's an inside joke now in the team. I've done it so many times but I keep crashing into the wall."

The Greek star couldn't help but laugh throughout her response. As she regaled the press with all the self-deprecating jokes she and her team have come up with regarding her 7-21 record in semifinals.

"Listen, I've lost so many semifinals and finals that if I don't see it that way and I keep being hard on myself and don't joke about it, it's going to be very tough to overcome," Sakkari said. Over the last three seasons, only Swiatek has made more tournament semifinals (21) than Sakkari. 

"It's my fifth semifinal of the year if you include United Cup. Consistency: that's part of Maria Sakkari. That's me. I've always had small little steps. Some people do it the easy way, some people do it the hard way."

Sakkari knows what she's up against in Sabalenka, who won their last meeting at Indian Wells in March. But this will be their first meeting on clay.

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[12] Veronika Kudermetova: Recovery

Kudermetova has advanced to her biggest career semifinal, and she's done it the hard way. With four consecutive three-set wins, including back-to-back Top 10 victories over No.8 Daria Kasatkina and No.3 Jessica Pegula, Kudermetova has spent 10 hours and 36 minutes on court. That's the most time en route to a Hologic WTA Tour semifinal in the past three seasons. 

"Right now I'm pretty fresh because I play only two hours," Kudermetova said jokingly after her win over Pegula in the semifinals. "Last matches I play almost three hours every match. I'm physically very strong, and in my mind was that thing that I can play three, four hours, doesn't matter what was the score, but I will fight."

Kudermetova's true breakthrough this week has been her ability to hold her nerve in the late stages of her last two wins. She saved match points to defeat Kasatkina in a third-set tiebreak and she held off any ideas of a comeback from Pegula to win 6-4 in the third. 

The key to her tournament has been her serve and aggression. Both will need to be on point if she has any hopes of breaking through Swiatek to notch a second straight Top 5 win. 

"I think she plays the men's style of game, because she does a lot of kick, she tries to play very aggressive," Kudermetova said. "I mean, if I'm looking at that, it's not giving me confidence. But I try to show my best, try to do the right things on the court."