At the Family Circle Cup players' party Sunday night, at a Charleston gathering place on Calhoun Street, 19-year-old Madison Keys did what a teenager should.

She had fun.

"I did," she said, flashing a smile at the memory. "At the photo booth, the dance floor, the candy bar. It was a fun party."

Things turned a bit more serious Monday afternoon on Billie Jean King Stadium Court. Keys, seeded No. 15 at the 42nd Family Circle Cup, had to gut out two tiebreakers on the way to a 7-6, 7-6 victory over Mirjana Lucic-Baroni of Croatia.

Keys was one of three seeded players in action Monday amid mild temperatures and under blue skies on Daniel Island. Ninth-seeded Lucie Safarova, a Family Circle Cup finalist in 2012, and No. 10 seed Maria Kirilenko of Russia also advanced with straight-set victories in the $710,000 tournament.

Other young Americans were not as fortunate Monday. Alison Riske, 23, and ranked No. 48, fell in three sets to No. 77 Chanelle Scheepers of South Africa; and Varvara Lepchenko, 27, and No. 46, lost in three sets to Petra Cetkovska. Christina McHale and wild-card entrant Melanie Oudin both went out in straight sets.

World No. 1 Serena Williams, seeking her third straight Family Circle Cup title, opens her bid at 7 p.m. Tuesday on Stadium Court. Her sister, Venus, is seeded 11th and faces Barbora Zahlova Strycova in match that won't start before 11:30 a.m. on Stadium Court. Venus will be followed on Stadium Court by 2010 Family Circle Cup champ Samantha Stosur.

Hometown favorite Shelby Rogers of Daniel Island opens Tuesday's play against No. 12 seed Daniela Hantuchova at 10 a.m. on Stadium Court.

Keys, from Rock Island, Ill., is ranked No. 36 in the world, making her the second-highest ranked teenager on the WTA Tour, behind No. 35 Elina Svitolina of Ukraine, who also is 19 years old.

That means that for Keys, finding a balance between fun and business is an ongoing project, just as it is for any teenager. It's just for Keys, who has won more than $750,000 since turning pro in 2009, the stakes are a bit higher.

"If you know me, you know I don't do serious very well," said Keys, who counts baking and shopping among the things she does for fun. "There's a time and place to be serious, but for me it's just about enjoying life."

Playing on clay courts is not one of the things Keys does for fun, but her breakthrough season last year included a run to the quarterfinals on the Family Circle Cup's green clay. There, she lost to her idol, Venus Williams, 6-4, 6-4.

"There are definitely times when clay frustrates me," said Keys, who gave up only three points in her two tiebreaks against Lucic-Baroni. "And I'm sure it's pretty obvious to other people. But it's something I'm really working on. It's just getting used to it and being more comfortable on it."

Another young American, 20-year-old Lauren Davis, looked comfortable in just her second appearance at the Family Circle Cup. Davis, ranked No. 62 and from Gates Mill, Ohio, continued a strong recent run of play with a 6-1, 6-4 victory over Germany's Dinah Pfizenmaier.

Davis knocked off world No. 4 Victoria Azarenka on the way to the round of 16 at Indian Wells last month.

Monday's scores

Chanelle Scheepers d. Alison Riske, 4-6, 6-2, 6-3

Lauren Davis d. Dinah Pfizenmaier, 6-1, 6-4

Teliana Periera d. Patricia Mayr-Achleitner, 6-1, 7-6

Lucie Safarova d. Johanna Larson, 6-2, 6-3

Virginie Razzano d. Julia Goerges, 6-0, 5-7, 6-2

Madison Keys d. Mirjana Lucic-Baroni, 7-6, 7-6

Petra Cetkovska d. Varvara Lepchenko, 6-1, 2-6, 6-0

Yaroslava Shvedova d. Saisai Zheng, 6-2, 3-6, 7-5

Ajla Tomljanovic d. Stefanie Voegele, 6-7, 6-1, 7-5

Kiki Bertens d. Paula Ormaechea, 7-5, 3-6, 6-3

Alla Kudryavtseva d. Christina McHale, 6-3, 7-5

Jana Cepelova d. Melanie Oudin, 7-6, 6-2