Question: Who was the first major athlete in the Soviet Union to demand publicly to keep their tournament earnings was Natasha Zvereva or Katarina Srebotnik?
Sentence (from "Katarina Srebotnik"): She reached a career-high singles ranking of No. 20 on the Sony Ericsson WTA Tour on August 7, 2006, and a career-high doubles ranking of No. 1 on July 4, 2011.
Relevant evidence: Yes