London, UK - 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 from 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, 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.

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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 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 gruelling. 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," she said.

"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.

The Czech refused an anti-doping test in December, saying she was scared to let a doping official into her house.