On the WTA tour at the moment, success on clay isn't about being the most comfortable on the surface -- just the least uncomfortable on it. Who would have thought that Maria Sharapova, once most famous on clay for comparing herself to a "cow on ice," would now be dominating on it, winning the past four big red-clay events in a row?
An in-form Sharapova started her clay campaign last week by defending her title in Stuttgart, Germany, which she won last year along with victories in Rome and at the French Open. Her opponent in the final was Li Na, who won the French Open in 2011 and lost to Sharapova in the Rome final last year.
And, although Sharapova has been asserting herself on the red stuff, Serena Williams has been cleaning up on the other varieties. She defended her title at Charleston on green clay a couple of weeks ago and won on the blue clay used at Madrid last year.
Victoria Azarenka also has been in the mix, reaching finals at Stuttgart and Madrid last year.
What do all these women have in common, apart from recent success on clay? None is particularly fond of the surface.
They grew up on hard courts, and their power-hitting game remains more suited to faster surfaces. But it hasn't stopped them from translating their results to the slower, higher-bouncing clay.
That's partly because most of their competition isn't much better off.
"You have a lot of players that are not really surface-orientated," ESPN analyst Darren Cahill said. "Everyone is playing quite a similar style and not really changing the way they play dependent on surface.
"That's why it's been a little easier for some of the so-called 'non-clay-court experts' to get results."
In some ways, it's not a new development. Historically, top female champions have managed to dominate no matter what the surface. But specialization seemed to be increasing a few years ago, with clay-suited players such as Justine Henin, Amelie Mauresmo, pre-retirement Kim Clijsters, Svetlana Kuznetsova and Elena Dementieva making it tough for those who weren't dirt-ballers, such as Lindsay Davenport, the Williams sisters or Sharapova, to break through very often.
This year, however, Serena is likely to be a French Open favorite, even though she counts only one French Open title among her 14 majors and lost in the first round last year in what was the second-biggest upset of the season after Rafael Nadal's defeat by Lukas Rosol at Wimbledon.
It reflects the relative lack of topflight opposition on the surface at the moment. No. 7 Sara Errani, last year's other French Open finalist, is the highest-ranked player who would be at her best on clay. There are a few others, such as 2010 French Open champ Francesca Schiavone, Carla Suarez Navarro, Lucie Safarova and 2011 Stuttgart champ Julia Goerges, but there is no one as formidable as four-time French Open champ Henin around to threaten other top-ranked players.
"They don't have anyone else that can really compete with them and really feel comfortable on the clay court," said Antonio Van Grichen, the former coach of Azarenka who is working with Jarmila Gajdosova and other Tennis Australia players. "Errani, Schiavone, [Suarez] Navarro, they are lacking the power.
"Even though Justine didn't have the same power as Serena or Sharapova, she had a lot of other solutions. Errani -- she's a very patient player; she grinds a lot; she hits a lot of balls deep; she knows how to play on clay, but she also lacks other things.
"Justine was more complete."
But the clay-court ascendancy of players such as Sharapova, Li and Serena is also partly about their own improved effectiveness on the surface.
After winning the French Open last year, Sharapova pointed to improved fitness and movement as the reasons for her improved results. "The experience that I have now has helped me to understand my own body better, and I know how long it takes me to recover," she said.
"I just felt more comfortable. Not just this year, but starting maybe last year, maybe the year before, I started moving a lot better. I started believing that I could, you know, play longer rallies."
Li might have seemed at a loss to explain her unexpected run to the French Open a year earlier but made adjustments to meet the demands of the surface. "Mainly for Li Na, she started being a little bit more patient," Van Grichen said. Tactically, she was better and more aware of the whole game plan, of how to play on clay courts.
And, more than a decade after she got her lone major win on clay, Serena's game also has evolved.
"She's become a smarter tennis player, as well," Cahill said. "You see her breaking down opponents now much than she used to do, playing to weak sides and weak areas of her opponent's game. She's put a lot more thought into constructing points.
"From the back of the court, she's much more patient than she used to be. And she's got the fitness; she knows she can stay out there for three hours if she needs to."
Serena has grown comfortable on the surface after playing on it for a decade and a half, enough to embrace the challenge. "I enjoy playing on the clay. I enjoy sliding. You have to be more consistent, but I like it," said the world No. 1, looking ahead to this part of the season in Miami.
The transition is easier because hard courts have become slower, she added. Azarenka, who grew up playing indoors in Belarus and on hard court in the United States, agrees that switching isn't as hard as it used to be.
"Definitely a little bit different, but the game on clay becomes more and more similar as on hard court," she said during last year's French Open.
But it hasn't helped improve its popularity among the players. Samantha Stosur, who has been effective at the French Open the past few years with her kick serve and topspin forehand, has always said she feels more comfortable with cement underneath.
Even No. 4 Agnieszka Radwanska, whose varied game seems made for clay (and was made on it), prefers the truer bounce and footing of hard courts.
"It is strange because at home I really love playing on clay," she said at Rome last year. "I am not practicing on hard courts. I don't even have a hard court in my city, and so I am practicing on other surfaces.
"But now with the tournaments, I am really liking to play on hard.
"Ninety percent of the season is on hard courts, and so I am used to it."
The explanation might be that Radwanska is forced to produce more of her own power on clay rather than being able to use her opponent's pace, Van Grichen says.
Sometimes, the widespread discomfort on the surface has meant opportunities for the small number of players who do like the dirt. Errani is a prime example. Most of her triumphs came at small clay events until she unexpectedly reached the 2012 French Open final. Schiavone, 2010 Rome champ Maria Jose Sanchez Martinez and Goerges are others who have won big titles while big names struggled to adapt.
But with order re-emerging on the women's tour, those openings have become smaller and the biggest clay titles are often being won by players who see it as their worst surface. Call it survival of the least unfit.