London - Seven-time champion Serena Williams has been fined $10 000 (R142 000) for damaging one of the All England Club courts with her racquet, officials said on Tuesday.
The 37-year-old American was sanctioned for an incident which took place during a practice session before the tournament got underway.
"The code given is for unsportsmanlike behaviour. The reason is court damage," a spokesperson told AFP.
Williams is in action twice later on Tuesday when she faces fellow American Alison Riske for a place in the semi-finals.
She then returns to Centre Court to partner Britain's Andy Murray in the mixed doubles.
The All England Club also handed down a $3 000 (R43 000) fine to Italian Fabio Fognini for unsportsmanlike conduct after a rant during his third round defeat to American Tennys Sandgren.
The Italian had said he hoped a "bomb" would explode at the All England Club.
Wimbledon men's singles quarter-finals line up (x denotes seeded player):
Novak Djokovic (SRB x1) v David Goffin (BEL x21)
Guido Pella (ARG x26) v Roberto Bautista Agut (ESP x23)
Sam Querrey (USA) v Rafael Nadal (ESP x3)
Kei Nishikori (JPN x8) v Roger Federer (SUI x2)
Wimbledon women's singles quarter-finals line up (x denotes seeded player):
Alison Riske (USA) v Serena Williams (USA x11)
Barbora Strycova (CZE) v Johanna Konta (GBR x19)
Elina Svitolina (UKR x8) v Karolina Muchova (CZE)
Simona Halep (ROM x7) v Zhang Shuai (CHN)