Vintage clay-court tennis has hit the Family Circle Cup. Welcome, Sara Errani.

While former champions Venus Williams, Sabine Lisicki and Samantha Stosur followed the trend in Thursday's round of 16 of big hitters fading out of the 42nd Family Circle Cup, grunt-it-out clay-court tennis may be ready to take over the tournament. That was right up Errani's alley as she marched into Friday's quarterfinals.

No. 6 seed Eugenie Bouchard of Canada, the hybrid-type athlete/tennis player between Errani's court wizardry and Williams' awesome power, withstood all of Williams' big serves and groundstrokes for a 7-6 (6), 2-6, 6-4 victory over the seven-time Grand Slam tournament champion.

Andrea Petkovic, the 14th seed, wasted little time in putting away erratic fourth seed Lisicki, 6-1, 6-0, in a 55-minute battle of Germans.

Serbia's Jelena Jankovic, another former champion and the second seed, posted a 7-5, 6-1 victory over Ajla Tomljanovic of Croatia, to set up a 1 p.m. Friday quarterfinal showdown with Bouchard on Billie Jean King Stadium Court.

In the night match, Czech Republic left-hander Lucie Safarova continued her mastery (9-2) over 2010 champion Stosur in a 3-6, 6-4, 6-4 victory as Safarova's strategy to concentrate on Stosur's backhand paid huge dividends in the comeback.

Safarova broke the Australian's serve in the 10th game of the decisive set to end the match. After Stosur saved one of a double match-point situation when 2012 runner-up Safarova flew an easy overhead long, Stosur's backhand on the second match point sailed over the baseline.

"It was part of my tactic that I have to get into her backhand side, which is so much weaker than the forehand," Safarova said. "I was trying to serve a lot of the lefty serves into her backhand."

Errani, the No. 3 seed and 2012 French Open runner-up, looks like a title contender after scoring a 7-6 (6), 7-6 (5) victory over world's No. 1 doubles player Shuai Peng of China in a sun-drenched mid-day match that lasted more than two hours.

"I love clay," was Errani's calling card in the post-match interview, repeating it several times.

Errani appeared to toy with the go-for-broke two-handed hitting Peng at times. The Italian gained a big lead (4-1) in the second set as well as both tiebreakers (6-3 and 6-2), then allowed Peng to make things almost too interesting as Errani had to overcome set points in each set.

"The important thing was to win more than finish in two sets," Errani said, the typical philosophy of a true clay-courter.

"She was looking like she was physically tired (down 4-1) and she was trying to hit the ball faster to finish the point . . . so I thought I had the match in my hands.

"Of course, I'm very happy to finish in two, but I'm more happy I won," added Errani, who will face 17-year-old Swiss qualifier Belinda Bencic in Friday's third quarterfinal.

Errani rallied from 15-40 in the 12th game to force the first tiebreaker and then Peng served for the second set at 5-4 and 6-5. But Errani showed amazing resiliency and shotmaking ability, even in the face of her 60-70 mph serves that at times Peng played ping-pong with to the corners for winners.

The headline match of the day between Bouchard and last American in the main draw Williams was full of dramatic moments, especially for the 33-year-old Williams, who said she wasn't at the top of her game this week. None were more dramatic than the 10th game of the decisive set when Williams was within one point of evening the set.

Instead, Williams drilled a forehand long, then netted a backhand before dropping a short volley over the net that Bouchard jumped on to hit a forehand to an open court to end the entertaining two-hour and 14-minute match as a hush came over the stadium.

"She played a lot more consistently than I did," Williams admitted. "I think my errors really hurt me a lot today, just a lot of up and down, a lot of errors."

Bouchard served for the first set against Williams but committed a pair of unforced errors while Venus turned her return game up a notch.

In the tiebreaker, Williams pounded away for a 5-3 lead, but with a set point at 6-5 she made two straight errors and finally could just watch as a Bouchard cross-court backhand landed in the corner to end the tiebreaker on the 14th point.

Bouchard, a 20-year-old with excellent defensive skills, felt she almost let the match get away from her in the second set by being too passive.

"In the second set, I was just a bit slow," Bouchard said. "I wasn't going for my serve enough.

"So in the third I kind of got back into it and I just tried to play my game. She can come up with great shots, but in the second set I was kind of letting her do that too much."

Bencic scored a 6-7 (4), 6-4, 6-1 win over Ukraine's Elina Svitolina, the world's highest-ranked teenager (No. 35) who upset fifth-seeded Sloane Stephens in the second round.

Slovakia's Daniela Hantuchova, the 12th seed, stayed alive with a 6-2, 6-3 victory over Teliana Pereira of Brazil on the Club Court where Serena Williams' conqueror, unseeded Jana Cepelova of Slovakia, knocked out 13th seed Elena Vesnina of Russia, 7-6 (4), 3-6, 6-3.

THURSDAY'S RESULTS

Round of 16

Sara Errani (3) def. Shuai Peng, 7-6 (6), 7-6 (5)

Eugenie Bouchard (6) def. Venus Williams (11), 7-6 (6), 2-6, 6-4

Andrea Petkovic (14) def. Sabine Lisicki (4), 6-1, 6-0

Jelena Jankovic (2) def. Ajla Tomljanovic, 7-5, 6-1

Lucie Safarova (9) def. Samantha Stosur (7). 3-6, 6-4, 6-4

Daniela Hantuchova (12) def. Teliana Pereira, 6-2, 6-3

Jana Cepelova def. Elena Vesnina (13), 7-6 (4), 3-6, 6-3

Belinda Bencic def. Elina Svitolina, 6-7 (4), 6-4, 6-1.

FRIDAY'S SCHEDULE

Billie Jean King Stadium Court

Doubles Quarterfinal (11 a.m.)

Singles Quarterfinals

Not before 1 p.m.

Bouchard vs. Jankovic

followed by

Safarova vs. Petkovic

followed by

Errani vs. Bencic

Not before 7 p.m.

Cepelova vs. Hantuchova