Felibert has appeared in three previous tour events and missed the cut in each one. She was not originally in the field for this tournament and planned to go through the qualifying tournament Monday, before being notified she had earned a spot as the second alternate.
A native of Venezuela who played collegiate golf at USC, Felibert took advantage of the opportunity by shooting a 65 at the Pinnacle Country Club.
She was one stroke in front of Shanshan Feng, who last month became the first player from China to win a major title when she won the LPGA Championship.
Karine Icher, Inbee Park and Mi Jung Hur all had a 67 while those at 68 included Ai Miyazato and Ryann O'Toole.
Defending champion and world No. 1 Yani Tseng shot a 73 and was tied for 77th place.