Deadspin state that a USADA official arrived at Williams’ house at 8:30am on June 14, when a standoff ensued as Williams protested against unfair treatment.
Williams, who is continuing her comeback from childbirth, has been tested five times by USADA this year – per their database – while her main American rivals have been tested twice, once or not at all.
A spokeswoman for Williams told Deadspin:
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Over her 23-year career in tennis, Serena Williams has never tested positive for any illegal substance despite being tested significantly more than other professional tennis players, both male and female – in fact, four times more frequently than her peers. She has vocally supported, respected and complied with USADA testing throughout her entire career. While she willingly continues to submit to testing, there is absolutely no reason for this kind of invasive and targeted treatment.

How often have her rivals been tested by USADA?

World rankingNo. tests in 2018
Sloane Stephens 41
Venus Williams92
Madison Keys 101
CoCo Vandeweghe 162
Serena Williams1835
Williams was not at home when the officer showed up, with an assistant letting them into her home. But when Williams found out, she contacted WTA CEO Steve Simon.
"I received a text from Serena and called her back and left a message," Simon told Deadspin. "She shared with me some concerns and questions she had about an out-of-competition drug test."
Simon referred Williams to Travis Tygart, the CEO of USADA, but no sample was given to the tester. Bizarrely, the incident only came to light due to Simon being overheard discussing the case on his mobile phone in San Francisco Airport.
As it was not a regular ‘whereabouts’ test – where athletes must provide a daily 60-minute availability window for testing – but a random test at an out-of-competition venue, it will not count as an official missed test, according to USADA.
Williams will make her Grand Slam return at Wimbledon in July, where she is chasing a record 24th major title.
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