Shelby Rogers won an all-American battle with Katie Volynets at Indian Wells 6-4 4-6 6-1 on Wednesday.
"She definitely has a very bright future and unfortunately only one of us could win today," Rogers said.
"She's one of the nicest girls I've met on tour and I look forward to seeing her more."
Next up for Rogers is a second round meeting with seventh seeded Maria Sakkari, who reached the Indian Wells final last year. Rogers holds a 3-0 lead in her career meeting with the Greek.
Last week's Austin Open winner Marta Kostyuk was bundled out 7-5 5-7 7-5 by Swedish qualifier Rebecca Peterson. Alize Cornet also suffered a surprise first-round exit, going down 6-2 7-5 to 427th-ranked Evgeniya Rodina.
Wildcard Elizabeth Mandlik defeated fellow American Alison Riske-Amritraj 6-3 5-7 7-6 to set up a second-round clash with twice Wimbledon winner Petra Kvitova.
Italy's Camila Giorgi, China's Wang Xiyu and Ukrainian Lesia Tsurenko were among the other first round winners at the Masters and WTA 1000 event in the Southern California desert.