The Top 3 players in the world -- Iga Swiatek, Aryna Sabalenka and Jessica Pegula -- will lead an action-packed middle Monday at the Mutua Madrid Open. All eight Round of 16 matches will be played, setting up the quarterfinalists at this year's first WTA 1000 event on clay. 

We break down the matchups below: 

[1] Iga Swiatek vs. [16] Ekaterina Alexandrova

Head to Head: 1-1

World No.1 Swiatek went undefeated on clay during her 37-match winning streak last year -- the longest this century -- but to date, she has yet to master Madrid. 

By the numbers: Swiatek rolls into Madrid fourth round

In fact, this is only her second appearance in Madrid. Last year, Swiatek rested her ailing right shoulder and missed the event.

By taking out Bernarda Pera on Sunday, Swiatek matched her previous result from 2021, when she fell to then-World No.1 Ashleigh Barty in the Round of 16.

"I want to win every tournament that I go to, but Madrid, for sure, is still this kind of tournament that I haven't figured it out for 100 percent," Swiatek said before her fortnight began. "So I just want to get the experience."

So far, so good. Swiatek has lost only five games in each of her first two matches this week, dropping serve only once in each of those victories. Her winning ratio at WTA 1000 clay-court events is more than 88 percent as she eyes a fourth-round meeting with Alexandrova.

Alexandrova has gone deeper than Swiatek in a Madrid draw -- she posted her career-best WTA 1000 result here last year, when she reached the semifinals. After splitting their two hard-court meetings, this will be their first matchup on clay.

[2] Aryna Sabalenka vs. [WC] Mirra Andreeva

Head to Head: First meeting

Sabalenka is the only former Madrid champion remaining in the draw. After methodically moving through her first two matches, she'll now take on the Cinderella story of the first week in the 16-year-old Mirra Andreeva. 

Five quick hits with Mirra Andreeva, the 16-year-old making her mark in Madrid

Into the fourth round in her WTA debut, Andreeva has wins over former US Open finalist Leylah Fernandez, 13th seed Beatriz Haddad Maia and reigning Australian Open semifinalist Magda Linette. 

She's done it all without losing a set. Now, facing the World No.2, Andreeva says she's ready to swing freely.

"I have nothing to lose," Andreeva said. "There is no pressure at all for me. There is some pressure on her, I think, because she's going to play a 16-year-old girl."

But Andreeva has yet to face down the power Sabalenka can bring from both the baseline and service line. The key for the 2019 champion will be holding her nerve and not getting rattled if Andreeva manages to keep it close and get the crowd on her side. 

[3] Jessica Pegula vs. [18] Martina Trevisan

Head to Head: Pegula leads 1-0

Last year in Madrid, Pegula reached her first WTA 1000 final while still ranked outside the Top 10. In retrospect, given her businesslike rise into the Top 3, the result was entirely sensible, especially on the faster clay of Madrid.

Pegula scrapes past Bouzkova to secure Round of 16 spot in Madrid

“I like the conditions here, when I’m playing well. … I guess that’s everybody, though,” Pegula said with a laugh after her second-round win. “But I do. I feel like it does suit my game a lot, it plays a little bit quicker. I can be aggressive and it pays off, you get rewarded for that.”

In Sunday’s third round, Pegula held off Marie Bouzkova -- against whom she had lost three of their four previous meetings -- facing 14 break points but ceding only two of those.

Pegula will need to stay collected against No.18 seed Trevisan. Italy’s Trevisan, who reached the Roland Garros semifinals last year, is at her career-high ranking and has not dropped a set in her Madrid main-draw debut.

Pegula won their only previous meeting in straight sets earlier this year, at the inaugural United Cup on hard court.

[8] Daria Kasatkina vs. [12] Veronika Kudermetova

Head to Head: Kasatkina leads 2-0

After making the Adelaide International 2 final in January, Kasatkina went into a hard-court slump, losing six of her next nine matches. However, her draws were tricky, with four of those six losses coming against players currently ranked inside the Top 30.

Video: Kasatkina beats Tsurenko to make fourth round

As expected, Kasatkina has turned a greater percentage of those showdowns into wins on clay. Since hitting the dirt, last year’s Roland Garros semifinalist Kasatkina has won five of seven matches -- although she has yet to beat a Top 20 player on clay this season.

Kasatkina will need to do that if she wants to progress to the quarterfinals, with No.12 seed Kudermetova in her way. Kudermetova squandered a match point in the second set of her third-round match against Anastasia Potapova, but she successfully regrouped to win in three.

Kasatkina can take confidence into the meeting knowing that she is undefeated against Kudermetova, with a 2-0 record at the tour level and three additional wins during their junior careers.

[9] Maria Sakkari vs. [26] Paula Badosa 

Head to Head: 1-1

In one of the marquee matches of the Round of 16, Badosa will reassume her role as the hometown favorite and take on Sakkari. It will be just their third meeting, but the two are friends and frequent practice partners. Badosa knows she's in for a clay-court brawl.

Badosa eases past Gauff on home soil in Madrid; faces Sakkari next

"I really love how she competes," Badosa said after her 6-3, 6-0 win over Coco Gauff in the third round. "I really like players like that, that they give all on court, and they go for it no matter what. I really respect these kind of players.

"I think it's going to be a battle between two warriors, two fighters. I hope the home crowd can get me back to that and I can get the win."

Twelve months on from coming to Madrid as the No.2 player in the world, Badosa's challenge is to manage the tricky emotions that come with playing at home while unwinding Sakkari's solid baseline game. Their last meeting was a three-set duel at 2022 Indian Wells, which Sakkari won 6-2, 4-6, 6-1.

"I would lie if it would be a normal tournament," Badosa said. "It was [one of my first WTA tournaments] when I was 17 years old. It was my first semifinals of a 1000. This tournament will always be special for me."   

[11] Barbora Krejcikova vs. [27] Petra Martic

Head to Head: First meeting

With two victories under her belt in the first week, 2021 Roland Garros champion Krejcikova has won matches in Madrid for the first time in her career. The Czech hopes to continue a solid season at WTA 1000-level, after winning the first WTA 1000 event of the year in Dubai.

2019 Madrid quarterfinalist Martic might be a tough out for Krejcikova in the Round of 16. The 32-year-old Croatian Martic has posted some of her best results on clay, including winning her two WTA singles titles on this surface (2019 Istanbul and 2022 Lausanne). 

[14] Liudmila Samsonova vs. [31] Irina-Camelia Begu

Head to Head: First meeting

Into her first Round of 16 in her second appearance, Samsonova is coming off a 6-2, 6-0 win over Jelena Ostapenko. But clay remains a tricky surface for Samsonova, who has won all four of her titles on hard courts and grass. 

Video: Samsonova takes out Ostapenko

Of the two, Begu is the better clay-courter, as evidenced by her 22-5 record across all levels last season on clay. That span included two titles in Palermo (WTA 250) and Bucharest (WTA 125K), as well as a Round of 16 run at Roland Garros.

[24] Elise Mertens vs. Mayar Sherif

Head to Head: First meeting

No.59 Sherif has enjoyed an outstanding run to her first Round of 16 in Madrid. The Egyptian has not lost a set, with wins over Camila Giorgi, 30th seed Anhelina Kalinina, and the biggest win of her career, over No.5 Caroline Garcia. Back on her favorite surface, Sherif  is looking to make the quarterfinals of a WTA 1000 event for the first time. 

Video: Sherif upsets No.5 Garcia

Mertens has also looked back to her vintage form this week. The former World No.12 has been clinical through her first two matches, losing a combined 11 games to Rebecca Marino and Jule Niemeier. Mertens is bidding to make her first WTA 1000 quarterfinal in exactly two years.