Angelique Kerber, the top overall seed at Wimbledon, is out of the tournament following a 4-6, 6-4, 6-4 loss to 14th-seeded Garbine Muguruza on Monday while Venus Williams continued her run at the All England Club..
The result ensures that Kerber will lose her No. 1 world ranking. Either Simona Halep or Karolina Pliskova will take over as the top-ranked player after the tournament. Halep also advanced Monday, while Pliskova lost in the second round.
Muguruza won despite 50 unforced errors, 40 more than Kerber committed.
Williams, the No. 10 seed, defeated No. 27 Ana Konjuh 6-3, 6-2 to move into the quarterfinals for the second straight year. Williams, 37, made her Grand Slam debut at the 1997 French Open, seven months before Konjuh, 19, was born.
"Winning never gets old at any stage in your career, ever, ever," Williams said.
Williams served pretty much impeccably, hitting seven aces and winning 31 of 36 first-serve points.
"I think I'm playing pretty solid," said Williams, who last won the title at the All England Club in 2008. "For me, it's about getting through the round. You're not going to play perfect every round. I would like to play, you know, in straight sets every round. That would be great. If not, all that matters is you win."
Halep is back in the Wimbledon quarterfinals, advancing with a 7-6 (3), 6-2 victory over former No. 1 Victoria Azarenka. Halep reached the semifinals at the All England Club in 2014 and played in the quarterfinals last year.
She will next face Johanna Konta, who claimed a 7-6 (3), 4-6, 6-4 win over Caroline Garcia.
CoCo Vandeweghe is into the quarterfinals for the second time after defeating fifth-seeded Caroline Wozniacki 7-6 (4), 6-4.
The 24th-seeded American had eight aces while Wozniacki had zero.
Wozniacki has yet to reach the quarterfinals at the All England Club in 11 appearances but has advanced to that stage at the other three Grand Slam events, including two US Open finals.
Vandeweghe also made it to the quarterfinals at the All England Club two years ago, when she lost to Maria Sharapova.
Earlier Monday, Svetlana Kuznetsova became the first player to reach the quarterfinals, as the two-time Grand Slam champion beat Agnieszka Radwanska 6-2, 6-4.
Muguruza and Kuznetsova will square off in the next round. They will be joined in the quarters by reigning French Open champion Jelena Ostapenko and Magdalena Rybarikova. No. 13 Ostapenko upset No. 4 Elina Svitolina 6-3, 7-6 (6), and Rybarikova eliminated Petra Martic 6-4, 2-6, 6-3.
Seeded seventh, Kuznetsova will be playing in the quarterfinals at the All England Club for the fourth time, but the first since 2007. She has yet to advance past that stage.
Radwanska, seeded ninth, made at least the quarterfinals five times in her 11 previous appearances -- including losing to Serena Williams in the final in 2012.
Ostapenko led 5-3 in the second set but was broken and forced into a tiebreaker. She finally won by converting her eighth match point and will face Venus Williams in the quarterfinals.
"She's such a great player," Ostapenko said of Williams. "I will just go on court and enjoy the match because I really have nothing to lose."
Before winning the title at Roland Garros last month, Ostapenko had never been past the third round at a Grand Slam. She was the first woman to win her debut tour-level title at a Grand Slam tournament since 1979. The 20-year-old Latvian won the girls' title at the All England Club in 2014.
Rybarikova, from Slovakia and ranked No. 87, had not advanced past the third round in any of her previous 35 appearances in the main draw at a Grand Slam. She missed nearly seven months after last year's Wimbledon because of injuries.
ESPN Stats & Information and The Associated Press contributed to this report.