Charleston - Second-seeded Ekaterina Makarova knew she wouldn't be her sharpest with only a day to work on the Family Circle Cup's slower, clay-court surface.
Makarova needed three sets to defeat Zhang Shuai of China 5-7, 6-3, 6-2 on Wednesday and move into the round of 16.
The 26-year-old Russian lost in the doubles final at the Miami Open on Sunday, giving her little time to adjust to the change in surfaces.
"To change really fast from the hard court to the clay, it's really tough," said Makarova, who added she had stomach pain and visited the doctor after the match.
Makarova, ranked eighth in the world, was down a set and trailing 2-1 in the second set.
She said Zhang was more aggressive in that stretch.
However, Makarova won five of the next six games to win the set. She closed it by winning the final four games in the third.
"In the important moments, I played really good today," she said.
Makarova is one of just two players ranked in the top 10 — No. 7 Eurgenie Bouchard is the other — competing at the Family Circle.
She sees an opportunity to make a mark early in the clay-court season.
"I'm really happy to come back, and I just really enjoy this tournament again and trying to show my best tennis," she said.
Makarova said each success at a tournament builds belief in her game and confidence to push forward.
"It's always good when you are winning tough match, maybe in three sets and not playing like your best, best tennis," she said.
"And it's every time getting you more confident, and it really helps."
The top-seeded Bouchard and No. 4 seed Sara Errani play later Wednesday.
No. 12 seed Belinda Bencic lost to qualifier Danka Kovinic 4-6, 6-3, 6-2.