Defending champion Serena Williams has powered her way into the U.S. Open quarterfinals, winning the last 10 games to beat No. 22-seeded Daniela Hantuchova 6-2, 6-0.

Williams finished with eight aces and a 27-9 advantage in winners in Sunday's first match in Arthur Ashe Stadium.

No. 1 Dinara Safina was upset Saturday night, meaning No. 2 Williams is the highest-ranked woman left in the field. Safina will remain atop the rankings, though, even if Williams were to win a second consecutive U.S. Open title and fourth overall.

Williams has reached the quarterfinals at 11 of the past 12 major tournaments and won the title at three of the past four.