Green clay, the great equalizer

Andrea Petkovic knows how to slide on green clay. Grace Beahm/Staff

There's something in a chemical compound unique to one patch of pristine Daniel Island real estate. Green clay mixed with WTA parity that comes with tournaments not featuring a strong run by Serena Williams produces strange results.

And so we have a Family Circle Cup final Sunday in which No. 14 seed Andrea Petkovic, ranked No. 40 in the world and with only two WTA titles to her name, is the overwhelming favorite.

Petkovic, 26, rallied past No. 6 seed Eugenie Bouchard in Saturday's semifinal. She will face dazzling 20-year-old Jana Cepelova, who outlasted Belinda Bencic, 17, in the first WTA semifinal for both players.

"I'm the oldest here?" Petkovic said, laughing. "Can you believe that? Oh, my God, I want to kill myself."

Bencic, ranked No. 140, got into the tournament as a qualifier.

Cepelova is ranked No. 78.

Madcap weeks like this have happened before.

Iva Majoli won the 2002 Family Circle Cup while ranked No. 58. At the time, she was the second-lowest ranked player to win a WTA title.

Sabine Lisicki, ranked No. 63, came out of nowhere - and Troisdorf, Germany - to win the 2009 Family Circle Cup. She stands as the lowest ranked Family Circle Cup winner, the only player to win the title without having won a previous WTA tournament.

But Cepelova lurks. This week's upset stretch raises the bar on green clay zaniness.

"I'm definitely going to be the favorite," Petkovic said before the second semifinal was over, "and they have nothing to lose."

Green clay is challenging enough by itself; the Family Circle Cup is the only WTA tour stop with such a surface. The hybrid composition - slower than hard courts but faster than red clay - is a nice transition to the clay-heavy European season leading to Roland Garros in late May.

"It's nice to have a clay court tournament in North America before we start the long European season," said Bouchard, who eliminated former Family Circle Cup champions Venus Williams and Jelena Jankovic this week.

But the charm of Charleston comes after grueling two-week tournaments at Indian Wells and Miami. Some of the players are already tired when they arrive in Charleston.

Experience helps, to an extent. Jankovic knows green clay; the animated Serb has played in 10 Family Circle Cups. She won the 2007 title.

Still, this week was a grind.

"It's not easy when you play your first time on clay and you play a lot of matches and you get tired," she said after losing a quarterfinal match to Bouchard. "It takes a little bit of time to get match-tough on this surface because the legs get so sore and all of this."

Mastering the art of sliding is the obvious key on clay. For Petkovic, it's been a particular challenge. She has been ranked as high as No. 10 in 2011 but suffered an ankle injury in 2012 while sliding on red clay.

"I was very afraid of sliding into my forehand side," Petkovic said, "and I've been working this week specifically on the practice court just trying to slide into my forehand and not losing a lot of time running through the shots, because that takes so much time."

Aggressiveness is the key, Petkovic said.

For lots of Saturday, Bouchard was the aggressor and in control - not just of a semifinal match but the tournament. The 20-year-old Canadian rising star was sliding and slamming balls into tight spots.

She seemed on the verge of her first WTA title.

Only to fall victim to Petkovic's steady slides to that trusty forehand side.

And green clay weirdness.

It won't be the last time Daniel Island's strange surface bites back. It will happen again, next year when Belinda Bencic is 18 and for many Aprils to come. Long after Eugenie Bouchard wins Grand Slam titles, marries a hockey star and retires rich.

Follow Gene Sapakoff on Twitter @sapakoff