Angelique Kerber crashed out of Wimbledon 2017 and lost her hold on the world number one ranking, while five-time champion Venus Williams became the oldest All England Club quarter-finalist in 23 years on Monday. Kerber was beaten 4-6, 6-4, 6-4 by Spanish 14th seed Garbine Muguruza as the German's fourth round exit extended a miserable run for last year's Wimbledon runner-up. The 29-year-old, who lost to Serena Williams in the final 12 months ago, has failed to make the last eight at any of this year's three Grand Slams. Kerber had taken the top ranking from Serena in March, but her Wimbledon defeat leaves her with a dismal 0-9 record against top 20 opponents in 2017.
She will be replaced at number one by either Karolina Pliskova or Simona Halep.
Halep takes on Victoria Azarenka in the last 16 later on Monday and the Romanian world number two will be guaranteed top spot if she makes the semi-finals.
If Halep loses before the last four, then Czech world number three Pliskova will be the new number one despite losing in the second round.
Muguruza, the 2015 Wimbledon runner-up, goes on to play Russian seventh seed Svetlana Kuznetsova for a place in the semi-finals.
With only two women's matches scheduled for Wimbledon's two main show-courts on Monday, Kerber was exiled to the less grand Court Two.
It was a decision that brought criticism for Wimbledon chiefs and Kerber was visibly frustrated by the state of surface after she slipped on several barren patches of grass on the baseline.
Despite her complaints, Kerber managed to take the first set, but Muguruza hit her stride as she took the second.
Kerber twice led by a break in the final set, but couldn't close out the victory as Muguruza showed she has been absorbing the lessons of her coach Conchita Martinez, the only Spanish woman to win Wimbledon back in 1994.
Granted showcourt billing, Williams didn't hang around as she crushed 19-year-old Croatian Ana Konjuh 6-3, 6-2 in 64 minutes on Centre Court.
Williams made her Grand Slam debut at the 1997 French Open, seven months before Konjuh was born.
And at 37 years and 29 days, Venus is Wimbledon's oldest female quarter-finalist since Martina Navratilova in 1994.
Seven-time major winner Venus, who clinched the last of her Wimbledon titles in 2008, will hope to emulate Navratilova, who went on to reach the final 23 years ago.
Williams plays French Open champion Jelena Ostapenko for a place in the semi-finals.
Ostapenko advanced to her first Wimbledon quarter-final after finally converting her eighth match point to defeat Elina Svitolina 6-3, 7-6 (8/6).
Latvian 13th seed Ostapenko, the 2014 junior Wimbledon champion, squandered seven match points in the second set before eventually seeing off the Ukrainian world number five to make just her second last eight appearance at a major.
The 20-year-old's triumph in Paris last month made her only the third player born in the 1990s to win a Grand Slam.
Kuznetsova reached her first Wimbledon quarter-final in 10 years with a 6-2, 6-4 win over Polish ninth seed Agnieszka Radwanska.
Kuznetsova, a former US and French Open champion, crushed 37 winners in her 14th victory in 18 meetings with Radwanska.
The 32-year-old has never made it to the Wimbledon semi-finals and last reached that stage at a Grand Slam in the 2009 French Open.
Slovakia's Magdalena Rybarikova is into her maiden Grand Slam quarter-final after a 6-4, 2-6, 6-3 win over Croatian qualifier Petra Martic.
Rybarikova, 28, had failed to make the last eight in all 35 of her previous Grand Slam appearances, losing in the Wimbledon first round for seven successive years between 2008 and 2014.
Next up for the world number 87, who has 17 wins from 18 grass-court matches this year, is a clash with either former world number one Caroline Wozniacki or American 24th seed Coco Vandeweghe.
Later on Monday, Britain's Johanna Konta, the bookmakers' favourite for the title, faces world number seven takes on France's Caroline Garcia.
Konta is aiming to become the first British women into the Wimbledon quarter-finals since Jo Durie in 1984.
Virginia Wade was the last Briton to win the women's crown in 1977.