Next American star?

American Madison Keys has advanced to the finals of the Family Circle Cup on Daniel Island. (Grace Beahm/Staff)

Along with a blistering serve and powerful forehand, Madison Keys has her sarcasm game switched on this week at the Family Circle Cup.

“I expect to win the French Open now, yes,” the rising American star said Saturday after reaching the first clay court final of her young tennis career. A Grand slam title on red clay might be a reach, but a breakthrough triumph on Sunday on the Family Circle Cup’s green clay certainly seems plausible.

Keys, 20 and seeded seventh, will face a formidable foe in No. 5 seed Angelique Kerber, who ousted friend, countrywoman and defending FCC champ Andrea Petkovic, 6-4, 6-4, in the other semifinal.

But the last time they met, Keys got the best of the 27-year-old Kerber, winning her first (and only) WTA singles title in three sets on the grass at Eastbourne last year.

“Angelique is obviously a great player,” Keys said of Kerber, who is ranked No. 16 and has won six WTA titles. “She’s made tons of finals, won tons of matches. No matter what, it will be a tough match. But at the end of the day, I’m more concerned with myself.”

Keys herself has been playing just great this week. In four straight-set wins, Keys has lost just 14 games and has not been broken on serve even once. Her road has not been the most difficult — she’s faced two qualifiers and players ranked No. 107 and 61 — but there’s no denying her level of play.

“It’s definitely kind of surprising,” said Keys, who is ranked No. 20 and made the semifinals at the Australian Open this year, her first Grand Slam semi.

“I don’t think the grass final (at Eastbourne) surprised people as much. But I’m really happy. It’s been a pretty good transition from hard court to clay court.”

Kerber faced an emotional challenge Saturday against Petkovic, the third seed and fan favorite who is now 11-1 in matches played at the Family Circle Cup. The two pals grew up playing against each other in junior tennis in Germany.

They shared a long hug at the net after Kerber clinched the match.

“It’s not easy to play against a good friend, a close one, actually” said Kerber, who began this year ranked in the top 10 but is just 12-9 in matches this season. “I think we both played very well and gave everything we could today.”

It was a disappointing end to her title defense for Petkovic, who made the semifinals at Miami two weeks ago and has battled fatigue all week on Daniel Island.

“I think Angie played a fantastic match,” Petkovic said. “She played really, really great tennis, and she didn’t give me any presents at all. She was rock solid today, and I think she played fantastic.

“I really wasn’t physically able to pull through the long and tough rallies, I think. I worked the point well and then I missed the easy one because I was exhausted most of the time.”

For her part, Kerber exhibited no sarcasm when she said she was not surprised to see Keys in a clay court final.

“She’s a very talented player and I think she can play on any surface,” she said. “She hits the ball, she has a great strong serve. I think it’s the first time we play on clay, so let’s see.”