Eighth seed Samantha Stosur had little trouble in advancing to the last 16 of the BNP Paribas Open in Indian Wells with an easy win over Anastasia Pavlyuchenkova.
The Australian dropped just three games in disposing of Pavlyuchenkova in 72 minutes.
Stosur was on top in the first set, a first-serve ratio of 63 percent 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.
Ninth seed Flavia Pennetta was an eye-catching casualty as Shahar Peer completed a three-set victory.
Italian Pennetta had battled back from a set down to win the second in a tie-breaker 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 clash against sixth seed Jelena Jankovic.
The Serb was forced to play her best tennis in a near three-hour encounter with Italy's Sara Errani, who took the first set in convincing fashion.
Jankovic rallied to take the second in a tie-breaker before just edging a keenly contested decider for a 2-6 7-6 (8-6) 6-4 win.
Third seed Victoria Azarenka of Belarus was the highest seed to crash out on a day of surprises.
Azarenka slumped to a 7-6 (7-4) 6-2 loss at the hands of 28th-seeded Spaniard Maria Jose Martinez Sanchez, while the 14th-seeded Kim Clijsters was also a high-profile third-round casualty.
The Belgian, who has made a strong return to the WTA Tour after coming out of retirement, had no answer to Russian 23rd seed Alisa Kleybanova, who posted a 6-4 1-6 7-6 (7-4) triumph.
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.
Spaniard Carla Suarez Navarro posted a 6-4 3-6 6-1 win over 27th seed Agnes Szavay of Hungary, while 13th-seeded Belgian Yanina Wickmayer saw off Italy's Roberta Vinci 6-1 3-6 6-3.