Pironkova started playing tennis at the age of four on being introduced to the sport by her father. She made her WTA Tour debut at the İstanbul Cup in 2005, and achieved moderate success early in her career. That changed in 2010, when she entered Wimbledon with a 1–4 career record at the event, and went on reach the semifinals of the tournament, becoming first Bulgarian tennis player in history to reach the semifinal stage of a Grand Slam in singles. She garnered wide recognition for her performance, and after her semifinal finish reached her highest singles ranking at No. 31 in September 2010. Pironkova followed it up with a quarterfinal run at the event the following year.