Why Serena Williams isn't the favorite in a deep French Open field

Sanchez-Vicario: Tough to pick a favourite from the women's draw (5:12)

Former world No. 1 Arantxa Sanchez-Vicario on the unpredictability of women's tennis, her rivalry with Steffi Graf and Monica Seles and more. (5:12)

Just when it seemed that the list of top women's contenders for the 2019 French Open couldn't get any longer, former world No. 1 Karolina Pliskova threw her proverbial hat into the ring by winning the Italian Open this past weekend. The direct-acceptance list for the French Open, which starts Sunday in Paris, features 13 current or former active Grand Slam singles champs, ranging from top-ranked Naomi Osaka to No. 102 Svetlana Kuznetsova.

"The top three may not be as strong as in some past times, but the top 15 are the strongest ever," ESPN analyst Pam Shriver told ESPN.com.

Still, one player towers over the field -- even if the long shadow she casts forms an enormous question mark. That's the Open era's most prolific singles title winner, Serena Williams, who has tasted more French Open success than anyone else in the field (28-4, with three titles).

Williams, 37, has played just four matches on clay -- the most challenging surface for her -- since returning from maternity leave in 2018. She's ranked No. 10, so her seeding won't protect her from facing tough opponents early. She withdrew due to injury from her only two clay events of 2018 and '19 -- last year's French Open (pectoral muscle) and, barely more than a week ago, the Italian Open (left knee).

"Serena is Serena, sure," ESPN analyst Patrick McEnroe said. "But you can say the same thing as you do for Roger Federer. Is he going to go out and win just because he's Federer? No. It's going to take a lot of work and hard matches played under stress and pressure. If Serena can win a few matches, anything could happen, but it's going to be difficult."

The problem for Williams is that, unlike Federer, she hasn't been healthy and hasn't banked any matches.

"She would show what an incredible athlete she is if she won the French Open," ESPN analyst Chris Evert said. "Because that would be an upset. Sure, if she's healthy and has a good draw the first week, she could play her way into it. She's notorious for being able to do that. But I have more belief that she can do something like that at Wimbledon."

Williams' legions of fans might have to wait -- or they can pick any number of other options. It was a difficult task, but we've winnowed down our focus to six additional French Open contenders. We're including the players' Universal Tennis Rating, which is their ranking based on their 30 most recent results over the past 12 months and provides a more accurate snapshot of their current form.

Naomi Osaka

WTA rank: No. 1
UTR rank: No. 8
2018-19 combined record on clay: 12-5
French Open career: 4-3
Best French Open: Third round, 2016 & 2018

Straight up, the stats of the top-ranked player in the WTA aren't at all impressive. But bear in mind that a year ago at this time, Osaka was just 20 years old and ranked a career-high No. 21. While she's primarily a hard-court player, she has shown signs of rapid improvement on clay this year.

"I think she surprised herself as well as other people," Evert said of Osaka, a semifinalist at Stuttgart and quarterfinalist in Rome. Osaka withdrew at those respective stages from those events (an abdominal strain and injured right hand, respectively), underscoring Evert's contention that being fresh and healthy might count for more at the French Open this year than ever before. "Her footwork, the sliding, they have improved tremendously," Evert said.

Osaka has been pleased, but she's still hungry. She said following her third-round win in Rome, "I feel pretty good. Semis, quarters, hopefully farther than quarters. I think that's good for me. I've never done this well on clay. I'm obviously looking to progress more."

Karolina Pliskova

WTA rank: No. 2
UTR rank: No. 4
2018-19 record on clay: 18-6
French Open career: 13-8
Best French Open: Semifinal, 2017

Shriver believes the WTA clay game has undergone a significant transformation in recent years, with sizeable power players eroding the advantage once held by counterpunchers. Small, quick and steady Simona Halep is the defending champion, but she has also lost two French Open finals -- both to bigger women who play a more aggressive game (Jelena Ostapenko and Maria Sharapova).

"If you can hit through the slower conditions," Shriver said, "you can do well at the French Open."

Pliskova, a 6-foot-1 former US Open finalist, is capable of just that. She has gotten over an early-career tendency to underwhelm at Grand Slams. True, Pliskova has never won a Grand Slam title, but she has been No. 1. Pliskova leads the tour in defending her serve, winning 63.2 percent of her serve points; her compatriot Petra Kvitova is a close second at 62.9 percent. Kvitova leads the tour in wins (28-8) this year, but Pliskova is 27-7.

Evert witnessed Pliskova's success in Paris in 2017 -- when she made the semifinals -- and made a mental note. "She's so efficient, not making errors, placing the ball well," Evert said. "Also, I love how calm she is out there. It's like nothing bothers her, whereas everyone else is getting all emotional."

Simona Halep

WTA rank: No. 3
UTR rank: No. 7
2018-19 record on clay: 23-5
French Open career: 27-8
Best French Open: Champion, 2018

The greatest tribute to Halep is a backhanded one: She doesn't lead the WTA in any statistical category (in her best category, Halep makes 69.5 percent of her first serves, fifth best on the tour). But the Romanian has been in the past two French Open finals thanks to her great wheels, superb groundstrokes and fighting spirit.

A number of factors suggest Halep might have trouble defending her title. She has struggled throughout her career when laboring under high expectations. There's also this: No woman has repeated as French Open champion since Justine Henin 13 years ago. At 5-foot-6, Halep has been punching above her weight for a long time.

The French Open has always been Halep's favorite major, and the Paris fans love her stamina and determination. She will get a lot of moral support.

"I give her just a slight edge as the favorite," Evert said. "She's just so solid, and she doesn't have as many ups and downs as some of the other contenders."

Petra Kvitova

WTA rank: No. 6
UTR rank: No. 1
2018-19 record on clay: 23-5
French Open career: 20-9
Best French Open: Semifinal, 2012

Kvitova became the first woman to win more than one title in 2019 when she locked down the victory at Stuttgart. Her 28-8 record this year leads the tour, and she ranks second only to Pliskova among top players in the break-points-saved department (60.7 vs. 60.9). Her 172 aces are fourth on the tour, and she also leads in double faults.

Kvitova has been within a set of the top ranking on two occasions and played a number of tournaments in which her performance could have lifted her to the top. But she's never been able to close the deal.

The 29-year-old, 6-foot power server maintained a solid record until forced to default last week at the Italian Open while trailing Greece's Maria Sakkari in their third-round match, citing a left calf injury. Kvitova's spokeswoman told Reuters in an email: "She is hopeful that it's nothing serious."

Kvitova has occasionally been undermined by her nerves, but her streak of inconsistency might be an even more damaging liability. "She's a shotmaker," Evert said, "so she's going to have a few more bad days than a player like Halep."

Kiki Bertens

WTA rank: No. 4
UTR rank: No. 2
2018-19 record on clay: 27-8
French Open career: 14-8
Best French Open: Semifinal, 2016

Bertens has been the revelation of this clay season and goes into the French Open with the hottest hand among the contenders. The 6-foot, 27-year-old from the Netherlands is a late bloomer who has never generated much buzz. But she has a whopper of a serve and an airtight, all-around power game to back it up. She ranks third on the tour, one tick below Pliskova and one above Kvitova, in that crucial first-serve points won category (72.3 percent).

Bertens debuted in the top 10 just last year and started 2019 at No. 9. The way she's built upon that has been "more than impressive," Shriver said. Since moving from the U.S. to European clay, Bertens has amassed a 12-2 record and made at least the semifinals in her past three tournaments. In winning Madrid, she didn't drop a set as she knocked off four Grand Slam champions, including Halep in the final.

"Kiki is such a mature, top player now," Shriver said. "It feels like her lows are close to her highs. She loves the clay, and her form is right there where you'd want it. The big question may be how she would react to rarefied air of a major semi or final."

Sloane Stephens

WTA rank: No. 7
UTR rank: No. 42
2018-19 record on clay: 18-8
French Open career: 23-7
Best French Open: Final, 2018

In 2017, Halep was up a set and a break on Ostapenko in the French Open final, only to surrender the lead and lose. Last year at Roland Garros, Stephens led Halep by a set and a break in the final only to blow the lead. Is it possible that pattern will continue?

At first glance, it's hard to imagine. Stephens has been as far as the semifinals just once in nine tournaments this year. That dismal UTR is statistical evidence of how hard it's been for the former No. 1 and US Open champion to get traction. It appeared she was trending up a few weeks ago with a semifinal appearance in Madrid, but she lost her first match in Rome.

Stephens has a solid history in Paris, though. She has reached the round of 16 four times. And there's no denying the explosive talent that lurks below her placid exterior.

"The only major that might be a bit of a reach for her is Wimbledon," McEnroe said. "Nobody can take the ball as cleanly off both wings as Stephens. If she would up her typical offense by about 15 percent, she could be a female version of Andre Agassi."

Stephens is now focused on developing a good working relationship with her new coach, Sven Groeneveld. He was instrumental in the success of (among others) Ana Ivanovic and Sharapova. He might be able to jump-start her game in time for the 2018 runner-up to make another run in Paris.

And if she finds herself down a set and a break in the final, she can just say to herself, "I've got it made now."