Tennis and the fact that both her daughters had failed in their attempts to lift another US Open trophy was largely an irrele-vance to Oracene Price. Like any mother, anxieties about her children’s health take precedence over anything else, and since Venus Williams won her fourth Wimbledon title two months ago, she has been giving cause for concern.

The problems came to a head as Venus lost to Justine Henin in the US Open semi-final. Players being attended to courtside by trainers has become commonplace in Grand Slam play, but few have their pulse or temperature taken.

Scenes in the corridors under Flushing Meadows’ Arthur Ashe stadium were even more alarming an hour after the 7-6 6-4 defeat. Venus cut a frail figure as she leaned on her boyfriend, PGA Tour golfer Hank Kuehne, and hobbled back to the sanctuary of the locker room.

Price stood in attendance, her face racked with maternal concern as she revealed that her daughter had been diagnosed with anaemia when she began to experience dizzy spells during a tournament in San Diego three weeks after her Wimbledon victory.

Rather than allowing Venus to return home to Palm Beach Gardens in Florida, Price is insisting on an immediate series of extensive medical tests to be carried out at the Mayo Clinic in Rochester, Minnesota.

“Today I guess the anaemia came back,” said Price. “Venus feels like the ground is moving beneath her feet. Things aren’t right and we have to find out what’s wrong.”

Viruses have been virulent in tennis locker rooms this summer. Marion Bartoli, the young Frenchwoman whom Venus beat in the Wimbledon final, was the first to suffer.

Since then Daniela Hantuchova and Jelena Jankovic have been affected. Nicole Vaidisova was sidelined for six weeks with glandular fever, and in this US Open men’s seeds Richard Gasquet and Tomas Berdych were forced to withdraw, complaining of illness.

The problems for the 12th-seeded Venus seem more serious, although she was full of praise for Henin, who beat her for the first time since 2001. Difficult though it is to comprehend, the 27-year-old Venus admitted to suffering throughout her impressive win over third-seeded Jankovic two days earlier, when she recovered from losing the first set.

“I’m not sure what’s wrong with me,” she said dolefully in a wavering voice that could not have been more different from the fierce persona she likes to portray on court. “I don’t feel the way I would feel if I had just played awfully and given it away. I feel like I was fighting some circumstances that I couldn’t conquer.

“I didn’t feel 100% at Wimbledon, but it’s definitely all about desire and will. I really wanted it there and I wanted it here too, but I fell short. I’m disappointed, obviously. I feel like I should have found a way, despite everything.”

As well as experiencing dizziness, Venus reported feelings of nausea and a general lack of energy. Although the temperatures and humidity in New York have been unseasonably high for mid-September, she did not blame the weather and pointed out that she prepares in the fierce heat of Florida. She could not remember what the trainer said to her courtside. “I was like in a zone. I was just hoping she had a magic pill. She gave me some jelly beans. I tried to eat them, but I was still feeling dizzy. It hasn’t been as much fun playing under these circumstances, because when you don’t feel good, it’s not fun. And I just want to feel good.” Although Venus has been a more consistent and mature competitor than her younger sister Serena, she has regularly suffered long absences because of injury.

She rose to become the top-ranked player in the world at the age of 21, winning back-to-back Wimbledon and US Open titles in 2000 and 2001, but since then there have been perpetual problems with tendonitis in both wrists.

In 2005 she broke a long drought when she became the lowest-seeded player (14th) to win a Wimbledon title, her first Grand Slam victory since 2001. She ended 2006 ranked 48th, but last July she won her fourth Wimbledon as the 23rd seed.

Amazingly, given the closeness of their relationship, she formed a pact with the rest of her family to keep her health issues secret from Serena. “She was my opponent in the draw too, so I didn’t tell her how I was feeling,” said Venus. “I never tell. She was having problems too, and I found out through someone else. We love each other, but we’re competing.”

Serena seems unlikely to get any tournament play in forthcoming weeks. Her father, Richard, revealed that she was unable to undergo the proper preparation after suffering leg and thumb injuries during her Wimbledon exit.

“She was in no position to play the US Open and her doctor tried to get her to stay home,” he said. “Serena could not move but if she is even halfway well, there is no girl who can beat her.”