The incident occurred on an outside court during a training session on June 30, the day before this year's grass grand slam began, according to organizers.
"I haven't really thought about it, to be honest," Williams, who has won more than $88 million in her career, told reporters after winning her quarterfinal against compatriot Alison Riske Tuesday.
"I just threw my racquet. I got fined."
When asked how she caused $10,000 worth of damage, Williams said: "I mean, I guess if you could tell me, I would appreciate it. I mean, I have always been an Avenger in my heart. Maybe I'm super strong, I don't know."
The American has previously been fined $10,000 at the All England Club for repeatedly smashing her racket on the court during a second-round victory over Christina McHale in 2016.
Australia's Bernard Tomic was fined his full Wimbledon prize money of $58,500 last week for not meeting the "required professional standard" during his lackluster 58-minute first-round defeat by Jo-Wilfried Tsonga.
Italy's Fabio Fognini was also docked $3,000 for saying a "bomb should explode" on the All England Club following his third-round loss to Tennys Sandgren Saturday.
Another Australian Nick Kyrgios has been fined twice -- $3,000 and $5,000 -- during this year's championships for incidents of unsportsmanlike conduct in his first and second-round matches.
Uruguay's Pablo Cuevas and Aryna Sabalenka of Belarus have also been fined $10,000 for incidents of unsportsmanlike conduct.
The 37-year-old Williams, who was also fined $17,00 for her remarks towards the umpire in last September's US Open final, is targeting a first Wimbledon title since 2016 and a record-equaling 24th grand slam victory.
She will play unseeded Barbora Strycova of ghe Czech Republic in Thursday's semfinal. Also into the last four in the women's singles are former world No.1 Simona Halep and eighth seed Elina Svitolina of Ukraine.
Williams and her mixed doubles partner Andy Murray reached the third round with a 7-5 6-3 victory against Fabrice Martin and Raquel Atawo later Tuesday.
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