Alexandra Eala, a 19-year-old wildcard from the Philippines, produced a huge upset at the Miami Open on Wednesday, defeating world number two Iga Swiatek 6-2 7-5 to reach the semi-finals.
Media reports said that Iga Swiatek was verbally harassed by a spectator, who has a history of online attacks against the player, during practice on Sunday.
Russian teen Mirra Andreeva ended defending champion Iga Swiatek's bid for an unprecedented third Indian Wells women's title, toppling the world number two 7-6 (7/1), 1-6, 6-3 on Friday to reach the final.
World number five Jessica Pegula believes the handling of high-profile doping cases involving Jannik Sinner and Iga Swiatek has shown that the "process is completely broken".
Jelena Ostapenko became the first player to defeat Iga Swiatek on five occasions.
Ekaterina Alexandrova also made the semis, beating sixth seed Jessica Pegula after her win over World No. 1 Aryna Sabalenka.
Australian Open: Madison Keys fought back from a set down on Thursday to shock Iga Swiatek in a nail-biter
Aryna Sabalenka and Iga Swiatek are clear favourites to win their respective semi-finals on Thursday and set up a blockbuster Australian Open title decider.
Top seed Jannik Sinner swept aside an out-classed home hope Alex de Minaur 6-3, 6-2, 6-1 to silence Rod Laver Arena and set up a meeting with 21st seed Ben Shelton.
WADA said that following a thorough review, it will not appeal against the ban given to Swiatek to the Court of Arbitration for Sport (CAS).