Third seed Victoria Azarenka has been knocked out of the BNP Paribas Open in Indian Wells by unseeded American Lauren Davis.
With her opponent hampered by a foot injury, Davis broke serve seven times en route to recording a 6-0 7-6 victory and a place in round three.
Prior to this match, Davis had never beaten a top 20 player.
She will now face Varvara Lepchenko in the last 16, after the world number 51 beat Daniela Hantuchova 6-3 6-2.