Akemi Nakata Khaiat opened with an even-par 72 and held a one-shot lead after Saturday's rainy first round of stroke play in the 52nd USGA Senior Women's Amateur at CordeValle Golf Course in San Martin.
Khaiat, who lives in Los Angeles and holds Japanese citizenship, just returned from her native land, too late for a practice round.
"I just listened to my caddie," she said.
San Rafael's Rachel Moreaux was tied for 10th with a 76.
Defending champion Ellen Port shot an 80. She was penalized two shots when her caddie accepted transportation. At USGA events, caddies must walk at all times.
After Sunday's stroke play round, the field will be trimmed from 132 to 64 for match play.
Austyn Carta-Samuels of Bellarmine College Prep threw for two touchdowns, as Vanderbilt (2-2) posted a 24-7 win at Massachusetts (0-4). Carta-Samuels completed 18 of 27 passes for 219 yards and ran for 38 yards. He also caught a pass for a 21-yard gain that set up his 11-yard scoring pass to Jordan Matthews.
The Associated Press contributed to this report.