The Australian committed only seven unforced errors and never faced a break point.
"I didn't realize I had so few errors so that's a good result," Stosur said. "To get 10 in a row is really good."
"I am feeling very comfortable on clay and everything is falling into place. I am really enjoying it," said Stosur, who has won 14 of her last 15 matches on clay, going back to the semi-finals of last year's French Open.
Stosur is projected to move up one place to a career-high No. 9 when the new rankings come out next week.
She is seeking her second title of the year after winning in Charleston.
Stosur will play either Lucie Safarova of the Czech Republic or Anna Lapushchenkova of Russia in the semi-finals.