Flavia Pennetta lost in the third round of the BNP Paribas Open as Shahar Peer completed a three-set victory in Indian Wells.
Italian Pennetta had battled back from a set down to win the second on a tie-break and take the match into a decider.
But her 17th-seeded Israeli opponent broke four times in a dominant third-set display to complete a 6-4 6-7 (4/7) 6-1 triumph and set up a last-16 clash against either sixth seed Jelena Jankovic or a second successive Italian opponent, Sara Errani.
There were no such problems for eighth seed Sam Stosur, who dropped just three games in disposing of Anastasia Pavlyuchenkova in 72 minutes.
The Australian was on top in the first set, a first-serve ratio of 63% helping her to a 6-3 success.
And she stepped up a gear in the second, winning 27 points out of 40 and converting all three of her break points to conclude a 6-3 6-0 win.
Russian 12th seed Vera Zvonareva eased past Latvian teenager Anastasija Sevastova 6-2 6-3 in 68 minutes despite wasting 11 of her 14 break points.
Second seed Caroline Wozniacki rounded out the day's action with an impressive 6-0 6-3 victory over Russia's Maria Kirilenko.