Sloane Stephens refused to blame the windy conditions for her 6-3 6-0 defeat to the Swiss qualifier Stefanie Vogele in the second round of the BNP Paribas Open.
The world number four could not come to terms with her opponent or the weather as she slumped to a heavy defeat at Indian Wells.
Vogele has won four of her five games against 2017 US Open champion Stephens, who said afterwards: "Obviously playing someone who you haven't done that well against in the past is a little bit rough.
"It was windy but it was windy for both of us. I just didn't play a great match."
Meanwhile, Serena Williams got the better of Victoria Azarenka 7-5 6-3.
The 23-times Grand Slam champion will play Garbine Muguruza in the third round after the Spaniard thrashed Lauren Davis 6-1 6-3.
Elsewhere, the unseeded Jennifer Brady defeated Caroline Garcia 6-3 3-6 6-0 while Ash Barty recorded a 6-4 6-4 victory against Tatjana Maria.
Marketa Vondrousova easily won her match against Daria Kasatkina 6-2 6-1 while there were also victories on Friday for the second seed Simona Halep, Jelena Ostapenko, Johanna Konta, Elise Mertens and Bianca Andreescu.
Halep is 1212/1 to win the Indian Wells tournament while Serena Williams can be backed at 1212/1.
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