With the French Open only a few weeks away, the Internazionali BNL d’Italia offers a wonderful red clay appetizer Thursday.

There are eight must-see matches, and among the 16 combatants are four of the past five champions at Roland Garros: Garbine Muguruza (2016), Jelena Ostapenko (2017), Ashleigh Barty (2019) and Iga Swiatek (2020). For a while, it looked like there’d be all five, but Simona Halep (2018) was forced to retire with a calf injury when leading Angelique Kerber 6-1, 3-3.

Halep was only part of the chaos in Wednesday’s second round, when five of the world’s top 10 departed in a flash: World No.2 Naomi Osaka, No.3 Halep, No.5 Sofia Kenin, No.8 Serena Williams and No.10 Petra Kvitova.

Three of these round-of-16 matches are first-time encounters. Here they are, broken down by quarters of the draw:

First quarter

No.1 Ashleigh Barty vs. Veronika Kudermetova

While a number of her top-10 colleagues are no longer in play, Barty needed to pull herself together after trailing by a break in the first set. She proceeded to win 10 of the last 11 games. Her 6-4, 6-1 victory over Yaroslava Shvedova was her tour-leading 26th victory.

Barty is in her 75th week as world No.1 and has won 17 of her past 18 matches on red clay, going back to that breakthrough win in Paris. Ten of those wins came this year in Stuttgart, where she won the title, and Madrid, where she lost to Aryna Sabalenka in the final.

Kudermetova, the 24-year-old Russian, has a game that potentially can stand up to Barty. After a terrific run on clay, she’s at a career-high No.28. Kudermetova won all six of her matches on the green clay at the Volvo Car Open, then reached the semifinals on red clay in Istanbul and the round of 16 in Madrid. In Rome, she’s beaten No.14 seed Elise Mertens in the first round and Caroline Garcia in the second. It all adds up to a 13-2 mark on clay for 2021.

This is their first meeting.

No.7 Aryna Sabalenka vs. Coco Gauff

Sabalenka is No.3 in the Porsche Race to Shenzhen and will move ahead of No.2 Osaka next week. She’s 25-6 – one win behind Barty – whom she beat in last week’s Madrid final. Sabalenka’s first victim in Rome was Sara Sorribes Tormo, 7-5, 6-1.

While Sabalenka is on a tear, the 17-year-old Gauff has an early track record of rising to important occasions. As a 15-year-old, she got to the round of 16 at Wimbledon and beat Osaka in the third round of the 2020 Australian Open. She has a 2-0 career record against Venus Williams.

Gauff knocks out Sakkari for R16 spot: Rome Highlights

Gauff is16-8 this year and has already reached two quarterfinals and a semifinal. This will be the third time they’ve met, with Gauff winning last year in Lexington and Sabalenka in Ostrava. Both matches went three sets.

Wins by Barty and Sabalenka would lead to their fourth meeting in 46 days.

Second quarter

No. 15 Iga Swiatek vs. Barbora Krejcikova

It hasn’t been a clean run for the 19-year-old Swiatek in Rome, but she’s finding form just in time to attempt a defense of her French Open final.

Madison Keys had her in trouble at 5-3 in Wednesday’s first set, before Swiatek found a way to win nine straight games.

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“It was tricky,” Swiatek said, “but I got into the rhythm. It came finally. It was a confidence-booster.”

Krejcikova, a 25-year-old from the Czech Republic, defeated No. 4 seed Sofia Kenin 6-1, 6-4. She’s ranked No.40.

The only time they met, Swiatek was a 6-4, 6-2 winner in Miami round of 16 back in March.

No. 5 Elina Svitolina vs. No.12 Garbine Muguruza

There 12th career meeting is the featured night match on Center Court, and with good reason.

While Svitolina has made more headlines for her engagement to ATP star Gael Monfils, her tennis has been newsworthy, too. She reached the semifinals in Stuttgart – beating two Grand Slam champions to get there – but fell to Barty in three sets. She dropped the first set to Amanda Anisimova but rallied to win 2-6, 6-3, 6-4.

Oddly enough, Muguruza also lost the first set 2-6 to American Bernarda Pera but came back to take the last two sets, 6-0, 7-5.

Although Svitolina leads the head-to-head 6-5, Muguruza has a 4-0 record in the weightier Grand Slams, most recently prevailing in the 2020 Australian Open.

Third quarter

No. 9 Karolina Pliskova vs. Vera Zvonareva

Zvonareva must feel like she’s playing with house money.

She’s 36, a mother (daughter Evelina was born in 2016) and into the round of 16 at a WTA 1000. Back in March, Zvonareva reached the semifinals on home soil at the St. Petersburg Ladies Trophy. The two-time Grand Slam finalist surprised No.11 Petra Kvitova 6-4, 3-6, 6-4.

Pliskova, meanwhile, had a relatively sedate 6-2, 6-3 win over Anastasija Sevastova. She won the title here two years ago and was a finalist in 2020.

Zvonareva has the 1-0 head-to-head advantage, a home game three years ago in Moscow, 6-1, 6-2.

Angelique Kerber vs. Jelena Ostapenko

Kerber found herself in the round of 16 when Halep, leading 6-1, 3-3, retired with a calf injury.

“I was feeling so bad for her,” Kerber said. “This was not the way I would like to finish a tough match against a good friend on the other side.”

Ostapenko won in straight sets over Ajla Tomljanovic.

This is one of three matches between unseeded players. Kerber won their only previous meeting, a 6-3, 6-3 result in the 2018 Wimbledon semifinals.

As Kerber noted, Ostapenko is a far more aggressive player than Halep.

“It will be completely different match,” Kerber said. “Also a good match before Roland Garros to have. I have to, yeah, be more aggressive, moving good. They are a little bit shorter rallies, but faster rallies.

“Let’s see tomorrow.”

Fourth quarter

Nadia Podoroska vs. Petra Martic

There will definitely, positively be a second and third unseeded player in the quarterfinals after Podoroska dispatched Serena Williams 7-6 (6), 7-5 and Jessica Pegula took care of Osaka 7-6 (2), 6-2.

“I think I play a great match,” Podoroska told reporters afterward. “This is the best tennis I play on clay. I think playing against her gave me a plus. I saw her playing when I grew up. It was a special match for me.”

Martic was a 7-5, 6-3 winner over lucky loser Kristina Mladenovic.

This is their first meeting.

Jessica Pegula vs. Ekaterina Alexandrova

This one promises to be close; Pegula is ranked No.31, while Alexandrova is No.33.

Pegula – who scored her best victory, rankings-wise, against Osaka – is at a career high and having a terrific 20-7 season.

“I’m not really a clay-court player, but I did grow up on green clay when I was younger in the States,” Pegula said. “I know she doesn’t love clay, so I just tried to be the clay-court player out there today and it worked, just good enough.”

Alexandrova received a walkover when No.13 Jennifer Brady withdrew with a left foot injury.

The two have never played.