Switzerland's Patty Schnyder has pulled off a second successive victory at the WTA tournament in Charleston, beating the former French Open champion, Mary Pierce.
The 23-year-old from Basel won in straight sets, 7-6, 6-2, to book a meeting with the powerful American, Serena Williams, in the quarter-finals.
Schnyder, who knocked out France's Amélie Mauresmo in the second round, has failed to beat Williams in their five previous matches.
Casanova run continues
Meanwhile young Swiss tennis star Myriam Casanova has continued her impressive run at the WTA tournament in Budapest.
Just 48 hours after celebrating victory in her first ever WTA singles match, the teenager from canton St Gallen has now booked herself a place in the tournament's quarter-finals.
Having come through the qualifying stages in Budapest before seeing off Croatia's Jelena Kostanic (WTA 82) in Tuesday's first round action, Casanova fought her way into the final eight on Thursday with a three sets win (3-6, 6-2, 6-4) over Slovakia's Lubomira Kurhajcova.
The 16-year-old Swiss Fed Cup team-member is currently ranked 348th in the world, although her performances in Hungary should see her rise dramatically when the new rankings are released on Monday.
A number of upsets for the seeded players in Casanova's half of the draw have left the Swiss youngster with a realistic chance of going even further still before the week is out.
In Friday's quarter-finals, Casanova is now set to face Bulgaria's Lubomira Bacheva (WTA 129) who accounted for Russian seventh seed Elena Bovina in the tournament's opening round.
swissinfo with agencies