Career
On 13 July 2015, she reached her best singles ranking of world number 65. On 27 July 2015, she peaked at world number 42 in the doubles rankings. Siniaková was ranked the number two junior tennis player in the world in December 2012.
In March 2013, Siniaková made her Women's Tennis Association tour debut in the qualifying draw of the 2013 Sony Open Tennis.
She defeated Mandy Minella and Alexa Glatch to qualify for the main draw, but lost a three-set encounter with Garbiñe Muguruza in the first round. Siniaková was born in Hradec Králové to a Czechoslovakian mother and a Russian father, Dmitry, a former boxer, who is Kateřina"s coach.
Doubles (2–2) Women's Tennis Association 125K series finals = Doubles (1–0) (6–0) Doubles (4–3) Girls" Girls" Doubles.