WIMBLEDON, England -- Walking away from Centre Court, Oracene Price -- mother and sometimes-coach to Serena and Venus Williams -- shook her head after watching one daughter lose at Wimbledon, then the other.
Undeniably great as she is, even defending champion Serena found it too tough to make a deep run at her first Grand Slam tournament in a year after a series of health scares. And as successful as Venus has been at the All England Club, even she couldn't muster her best after missing nearly five months with a hip injury.
"I don't think their layoffs helped their rhythm," Price said. "They both seemed to be making the same kinds of mistakes. They were hit-and-miss, here and there."
They're both headed home after straight-set exits in the fourth round against far-less-accomplished opponents Monday. First, 13-time major champion Serena lost 6-3, 7-6 (6) to ninth-seeded Marion Bartoli on Court 1. Then, less than two hours later and before a Centre Court crowd that included Prince William and his new bride, Kate, five-time Wimbledon champion Venus was beaten 6-2, 6-3 by 32nd-seeded Tsvetana Pironkova.
Adding to the chaotic nature of the afternoon, top-seeded Caroline Wozniacki lost, too, although she's still searching for her first Grand Slam singles trophy, whereas the Williams sisters own a total of 20.
"Definitely not our best day," Venus said. "I think we both envisioned seeing this day going a little bit different."
And why shouldn't they have? After all, Venus and her younger sister combined to win nine of the past 11 Wimbledon titles, including Serena's victories in 2009 and 2010. They even played each other in four of the finals in that span.
"Well, I never came here thinking I would lose," said Serena, a former No. 1 whose ranking now will plummet to about 175th. "That's my attitude."
It's the first time since 2006 that neither Williams is in the Wimbledon quarterfinals; Venus lost in the third round that year, while Serena skipped that tournament because of a left knee injury. Of the 12 years that both entered the field at the All England Club, this is the first neither one made it past the fourth round.
"Obviously, it's not something planned," Venus said. "We rarely lose on the same day."
That's true: They last lost on the same day at a Grand Slam tournament on May 30, 2008, in the French Open's third round.
All in all, it was a topsy-turvy day at the All England Club. Set aside, for a moment, what went on with the Williams sisters, and digest Monday's various other happenings:
• Wozniacki still has yet to make it past the fourth round at Wimbledon after a 1-6, 7-6 (5), 7-5 defeat against No. 24 Dominika Cibulkova;
• Defending champion and top-seeded Rafael Nadal initially thought he broke his left foot and might have to quit late in the first set, then lost the second set, but eventually beat 2009 U.S. Open champion Juan Martin del Potro 7-6 (6), 3-6, 7-6 (4), 6-4;
• Six-time Wimbledon champion Roger Federer dropped his first set of the fortnight -- against a man he was 10-0 against, no less -- before righting himself to reach a 29th consecutive Grand Slam quarterfinal;
• 18-year-old Bernard Tomic of Australia became the youngest man in the Wimbledon quarterfinals since 1986, when Boris Becker went on to win his second title in a row;
• 2010 runner-up Tomas Berdych went out in straight sets against 10th-seeded Mardy Fish, who never before reached the quarterfinals at the All England Club but now is the last American, man or woman, left in the tournament.
"Last ... Not what you set out to do," said Fish, who is 0-5 against Nadal heading into their quarterfinal. "It was, I guess, bad luck for the Williams sisters to lose. Unfortunate, I guess. They'll be back, I'm sure."
They won't be around for the women's quarterfinals Tuesday, which are: Cibulkova of Slovakia vs. No. 5 Maria Sharapova of Russia; Bartoli of France vs. wild-card entry Sabine Lisicki of Germany; No. 8 Petra Kvitova of the Czech Republic vs. Pironkova of Bulgaria; and No. 4 Victoria Azarenka of Belarus vs. Tamira Paszek of Austria. It's the first time since 1913 that the last eight women at Wimbledon are from Europe -- and, as it happens, eight countries are represented.
Sharapova is the only quarterfinalist who's won a Grand Slam title; her three major championships include Wimbledon in 2004.
After a day off, the men play their quarterfinals Wednesday. In addition to Nadal vs. Fish -- assuming Nadal decides to play after getting an MRI exam on his foot -- the matchups are No. 2 Novak Djokovic vs. Tomic; No. 3 Federer vs. No. 12 Jo-Wilfried Tsonga; and No. 4 Murray vs. unseeded Feliciano Lopez.
"I'm worried, for sure," Nadal said.