NEW YORK (Reuters) - Defending champion Serena Williams beat unseeded Yaroslava Shvedova of Kazakhstan 6-3 6-1 on Friday to set up a U. S. Open fourth-round clash with fellow American Sloane Stephens.
Four-time U. S. Open winner Williams grabbed the only service break of the first set in the sixth game and immediately seized the advantage by breaking the 78th-ranked Shvedova in the opening game of the second set.
The routine victory moved the world number one and top seed into the round of 16 against 20-year-old Stephens, who defeated Williams in the quarter-finals of this year's Australian Open.
The 15th-seeded Stephens defeated compatriot Jamie Hampton 6-1 6-3 in her third-round match.
(Reporting by Larry Fine, Editing by Nick Mulvenney)