Serena Williams has joined her sister Venus in the round of 16 at the US Open after a crushing victory over Ai Sugiyama.
The fourth-seeded American, the winner at Flushing Meadows in 1999 and 2002, was simply too powerful for the Japanese, winning 6-2 6-1 in 66 minutes.
Williams broke twice in the opening set and twice more in the second to set up a meeting with either Severine Bremond or Tathiana Garbin.
Venus was equally impressive in beating Alona Bondarenko in straight sets earlier on day six.
The seventh-seed was far too strong for the 24-year-old Ukrainian, winning 6-2 6-1 in just 55 minutes.
Williams dominated the first set, her powerful all-court game putting her in control.
She blasted 14 winners but made 16 unforced errors as Bondarenko simply struggled to stay in the contest.
The second was equally emphatic, Williams racing into a 5-0 lead before Bondarenko finally got on the scoreboard.
Next up for Venus is a clash against ninth seed and rising star Agnieszka Radwanska of Poland.
Radwanska shot out of the blocks on her way to a 6-0 6-3 triumph over 18th seed Dominika Cibulkova.
The battle of the Frenchwomen was won by Amelie Mauresmo, the former world No.1 too classy for compatriot Julie Coin in a 6-4 6-4 result.
Nadia Petrova of Russia was ousted by Italian Flavia Pennetta in a three-set tussle, 4-6 6-4 6-3.
Later on day six, Russian Dinara Safina rallied to defeat Swiss teen Timea Bacsinszky 3-6 7-5 6-2 in two hours.
The sixth seed will face Germany's Anna-Lena Groenefeld, who became the first US Open women's qualifier since Anna Kournikova in 1996 to reach the fourth round by defeating France's Alize Cornet 6-4 7-5.