Serena Williams has slammed the drug test rules that force tennis stars to declare their location to doping officials, claiming the "unprofessional" system stopped her coming out of retirement sooner.
Williams will play her first singles match since 2022 when the American legend faces Australia's Maya Joint in the Wimbledon first round on Tuesday.
The 44-year-old has made a sensational comeback after four years in retirement, far playing doubles at Queen's Club and Berlin before deciding to step up her return at Wimbledon, where she will also compete with sister Venus in the doubles.
Williams' stunning decision to pick up a racquet again has brought unwanted stress off the court however.
The 23-time Grand Slam champion had to enter the anti-doping testing pool several months before being allowed to officially return to the women's tour.
Tennis' 'whereabouts rules' require players to give a location and time slot when they can be tested for each day of the year.
Refusing one, or failing to update whereabouts three times within 12 months, can lead to a player being sanctioned.
Players can also be randomly tested at any time.
Williams is unimpressed by the testing system, which has changed since she last played.
"It's grueling. They changed the rules now. I didn't know some of the rules. So apparently if you miss a test outside of your window, it still counts as missed. I'm like, I guess I can't go pick up my kids," she told reporters at Wimbledon on Sunday.
"It's unprofessional. I hate it. It's necessary, but I think a lot of the stuff, if I want to go places outside of my window, I should be able to go without having it count as a missed test.
"There has to be a different way to make it reasonable because that's just unreasonable. That was a big reason why I didn't want to come back either, because it's just so hard."
Williams' blast comes just days after the International Tennis Integrity Agency handed a four-year ban to former Wimbledon champion Marketa Vondrousova, AFP reported.
The Czech refused an anti-doping test in December, saying she was scared to let a doping official into her house.
Williams is a mother of two young daughters and the drug test demands are an awkward addition to her daily schedule.
The seven-time Wimbledon winner knows testing is necessary to keep the sport clean, but adapting to the routine is a work in progress.
"My life is busy. I run a venture capital company, I travel the world. I have children. I could be in so many different cities so many different times," she said.
"But just getting that discipline of reporting. Obviously I don't mind because I always have been very clear about what I do.
"I guess now for 24 hours where I'm going to be is just different - at least for me. I don't know if that works for everyone else."
Williams' remarkable career looked to be over after she said she was "evolving away" from tennis in 2022 after a third round defeat against Ajla Tomljanovic at the US Open.
Even now, Serena is not quite sure she made the right decision to return to compete in singles after so long away.
"I had until Monday to decide. I think it was like Sunday. I just wasn't sure up until then.
Honestly, I'm still not even sure, but we'll see," she said.
Motivated to return by a desire to play in front of her children, Williams added: "My expectations are definitely different for the first time in my career. I feel like I'm really going to enjoy being out there.
"I expect to be nervous. I was also nervous every single match I ever played in my life. I think that showed the passion and the love and the care.
"I've always had some nerves. But I just dust 'em off, then I move on."
