The world's number one player beat Camila Giorgi 6-2, 6-3 on Tuesday, losing her serve in her second game and looking uncomfortable when the Italian was able to get Williams running.
"It was definitely not great for me. I think I played well, but I wasn't great footing-wise. I was just trying to get my stability," Williams said.
Williams nearly was broken again up 3-2 in the first set. She lost the first three points of the game before rallying back to win the next five. Giorgi wouldn't get another chance to break Williams the rest of the match, and only won two points against Williams's serve the entire second set.
Williams said she figured she would start slow because she only got one day of practice on clay to adjust from the fast, hard surface at Key Biscayne where she won the title for the sixth time on Saturday to the green, slow clay in Charleston, where she is the top seed.
"It was a little awkward for me," said Williams, who at 31 is the oldest woman to ever have the world's top ranking.
She also was facing a 21-year-old rising star in Giorgi, who caught Williams's eye last year by making it to the fourth round at Wimbledon.
Williams's slow start
"I actually have been watching her. I think she is a good player and I knew one day I'd be playing her," Williams said.
Giorgi had only herself to blame for not taking advantage of Williams's slow start. She had eight double-faults in the first set and 12 for the match. Williams's broke serve in the first two games as Giorgi's second serves went into the net each time.
Williams advances to the third round and just as importantly gets a day off on Wednesday. She said she plans on hitting just a few balls, but mostly resting. And if last year is any indication, Williams should get stronger as the tournament goes on. Williams won her opener 6-3, 6-4 in the 2012 tournament, and then lost seven games the rest of the week.
The biggest upset on Tuesday was Stefanie Voegele beating seventh-seeded Carla Suarez Navarro 6-2, 6-4. Jessica Pegula beat number eight seed Mona Barthel 7-6, 6-1 and qualifier Vania King defeated number 14 seed Yaroslava Shvedova 4-6, 6-1, 6-4.
All the other seeded players won on Tuesday, including number nine seed Jelena Jankovic who beat Melanie Oudin 6-4, 5-7, 6-4 in a match that took nearly three hours. It was Jankovic's first win over Oudin in three matches.
"She has this game that I really don't like and doesn't really suit me," Jankovic said. "I always have trouble with her."
'I love the green clay'
Jankovic, who won in Charleston in 2007, wasn't the only former Family Circle Cup champion to win on Tuesday. Number 15 seed Sabine Lisicki, the 2009 winner, beat Anna Tatishvili 6-0, 6-0.
"It's nice to play on the clay court," Lisicki said. "The quick turnaround is not always easy, but I love the green clay."
Other seeded players to advance were number 10 Julia Goerges, number 11 seed Sorana Cirstea and number 16 seed Laura Robson.
Number 4 seed Sloane Stephens plays on Tuesday evening. – Sapa-AP