Hingis also won the $520,000 indoor tournament in 1996, her first professional singles title, and in 1997. She needed just 65 minutes to earn this year's first prize, a convertible.
"I still have a little place in the garage," she said. "It's always special to play here, where I won my first title."
The fourth-seeded Pierce has been practicing with Hingis for a week but it didn't help her.
After trading breaks of serve, Pierce dropped her serve again in the seventh game and never recovered.
Under pressure from Hingis, she could not hold serve at the start of the second set. She saved three break points in the third game but a forehand winner by Hingis made it 3-0.
Hingis then had to save two break points to hold for 4-0.
With Pierce serving to stay in the match, Hingis forced her into a backhand error that gave Hingis a match point.
A hard-hitting rally ended with Pierce's forehand sailing wide.
"All in all, I am happy with the way I played here this week," said Pierce, who won here in 1993 but is still without a title this year. She settled for $40,000.
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