After withdrawing from her second-round match against 22nd-seeded German Sabine Lisicki, Venus Williams issued a statement describing the illness she said had kept her from playing all summer.
"I'm really disappointed to have to withdraw from this year's U.S. Open. I have recently been diagnosed with Sjogren's syndrome, an autoimmune disease which is an ongoing medical condition that affects my energy level and causes fatigue and joint pain," Williams said.
"I enjoyed playing my first match here and I wish I could continue but right now I am unable to. I am thankful I finally have a diagnosis and am now focused on getting better and returning to the court soon."
Lisicki, 21, who was a semifinalist at Wimbledon, was expected to give Williams an interesting test. Instead Williams will see her ranking drop to outside the top 100. Before the U.S. Open, Williams hadn't played a match since her fourth-round loss at Wimbledon, previously citing a viral illness, and she has played in only four tournaments in the last 12 months because of an assortment of injuries.
Williams, 31, won her 60th U.S. Open match Monday night on Arthur Ashe Stadium, in straight sets over Russian Vesna Dolonts, Williams, until this year, had reached at least the fourth round here every time she has played and is a six-time semifinalist.
The Sjogren's Syndrome Foundation website describes the ailment as "a chronic autoimmune disease in which a person's white blood cells attack the moisture-producing glands. Today, as many as 4 million Americans are living with this disease.
According to the Mayo Clinic website, Sjogren's often accompanies other autoimmune diseases such as lupus and rheumatoid arthritis, though Sjogren's is treatable and can be well-managed.
Williams, who was not seeded in this year's Open, waved gently to the fans as she left the grounds of Arthur Ashe Stadium after issuing her statement.
Earlier, Williams spoke of her summer-long illness, calling it "energy-sucking." It had not kept her from making sponsor appearances or designing her black, white and pink dress for her first-round appearance.
U.S. Open: Venus Williams wins first match since Wimbledon
U.S. Open: Carolina Wozniacki wins one, talks Rory McIlroy too
U.S. Open: Novak Djokovic wins easy opener; Donald Young too
-- Diane Pucin in New York
Photo: Venus Williams during her first-round match at the U.S. Open. Credit: Andrew Gombert / EPA.