Fassi, the rising Mexican star who was runner-up at the Augusta National Women's Amateur, played bogey-free at Blessing Golf Club for a 5-under 68, giving her a four-shot victory over Sierra Brooks of Florida.
Hailee Cooper had a 69, the only other sub-70 score. That was part of a big day for Texas, however, as the Longhorns claimed the No. 1 seed for team play.
Also qualifying for match play were Duke, Southern Cal, Wake Forest, Arizona, Stanford and Auburn.
Defending NCAA champion Jennifer Kupcho of Wake Forest, who won the Augusta National Women's Amateur in April, had a 72. She never had a chance to repeat her NCAA individual title after opening with 78-76, but she led a strong day for the Demon Deacons and will at least get a chance in team play.
The quarterfinals and semifinals are scheduled for Tuesday, with the championship match on Wednesday.
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