The Family Circle Cup draw was stacked with star names, including recently returned Venus Williams.
Serena Williams was also in the draw and put her historic game on display for fans Tuesday night.
Serena Williams' serve has looked good all week - she hit 11 aces in her opener with Elena Vesnina.
More American legends, Liezel Huber and Lisa Raymond, met fans at a luncheon earlier in the week.
Another American veteran, Jill Craybas, dropped copious amounts of knowledge during a suite visit.
There were a few weather delays earlier in the week, including during Wednesday's night session.
Venus Williams and Jelena Jankovic walked off the court in the first set with lightning in the area.
Upon resumption, Venus Williams won 12 of 14 games to complete a 75 60 win over Jelena Jankovic.
Polona Hercog pulled off the biggest upset of the first five days, beating No.3 seed Marion Bartoli.
Serena Williams had little trouble in her third round match, beating Marina Erakovic in straights.
Serena Williams is playing the Family Circle Cup for the first time since winning the title in 2008.
Polona Hercog made the rounds around the grounds and suites after reaching the quarters Thursday.
Sabine Lisicki took the court against Serena Williams in the first quarterfinal on Friday afternoon.
Down 4-1 first set Sabine Lisicki injured her left ankle and had to retire against Serena Williams.
Serena Williams consoled Sabine Lisicki at the net after the match. Both are Family Circle Cup winners.
Serena Williams moved into the semifinals, where she will face Sam Stosur, who beat Venus Williams.
Venus Williams had beaten Sam Stosur in all four of their previous meetings in routine straight sets.
But Venus Williams was just edged this time, losing to Sam Stosur in a tight three-setter, 63 46 63.
Lucie Safarova served up a 63 63 upset over Vera Zvonareva in the third quarterfinal of the day.
Polona Hercog rounded out the final four, playing flawless tennis to rout Nadia Petrova, 61 62.