Christina McHale sprung a surprise in the BNP Paribas Open with a straight-sets victory over Caroline Garcia at Indian Wells.
McHale made the best start possible when she broke Garcia in the opening game of the match and behind a strong serve went on to win 6-4 6-4.
"I knew I had to serve well because Caroline is so aggressive and I knew I had to get a lot of first serves in today, and it worked today so I'm excited," McHale said.
McHale will play the fourth-seeded GarbiÃ±e Muguruza in the next round and added: "I actually lost to her the last time we played and she's obviously playing really, really well. I'll try to play my best tennis and I'm looking forward to that match."
Magdalena Rybarikova ended Laura Robson's return to the top level with a 7-6 (7/3), 6-2 win, while Annika Beck eased through with a 6-2 6-2 win over America's Bethanie Mattek-Sands.
Yanina Wickmayer recovered from losing the first set to love to record a 0-6 6-4 6-4 win over Polona Hercog and Eugenie Bouchard also recovered from a poor start, beating Risa Ozaki 2-6 6-4 6-2.
On the first day in the men's event, Argentina's Leonardo Mayer booked a second-round clash with Viktor Troicki following a 6-4 6-3 victory over Sam Groth and Nicolas Mahut ended the interest of another Argentine's tournament with a 6-2 6-4 win over Renzo Olivo.
Highly-rated young Americans Frances Tiafoe and Taylor Fritz faced off with Tiafoe getting the better of the match 6-3 2-6 6-3, with another emerging youngster Borna Coric coming through 6-2 7-5 against Lucas Pouille.
Nicolas Almagro was beaten 5-7 6-3 6-4 by Spanish compatriot Inigo Cervantes and Guido Pella recovered from the jaws of defeat to beat Great Britain's Kyle Edmund 6-7 (3/7) 6-4 7-5.