In January 2006, Pironkova made headlines by defeating tenth-seed Venus Williams in the first round of the 2006 Australian Open by a score of 2–6, 6–0, 9–7. Pironkova was ranked 94th in the world.She played in the qualifications of the US Open, and beat Zuzana Ondrášková, Marta Domachowska, and Stéphanie Dubois to reach the main draw. She drew Olga Puchkova from Russia in the first round. Pironkova won that match 6–3, 6–4 to set up a clash with world number 1, Justine Henin in the second round. Pironkova lost to Henin in straight sets 6–4, 6–0. Pironkova qualified for the loss of only 10 games in 3 matches, won her first round match for the loss of just two more, and then took a 7–6, 3–1 second-round lead over Belgian World No.1 Justine Henin before losing the match in three sets.
She caused another upset at the 2008 Rome Masters. As a qualifier, she beat top seed and world no. 3 Ana Ivanović in the second round for the biggest victory of her career so far. She advanced to the quarterfinals, her first ever at a Tier I event, when Victoria Azarenka retired during their third round match with Pironkova leading 6–1, 1–0. In the quarterfinals she was defeated 6–2, 3–6, 6–1 by Anna Chakvetadze.
she lost to World no. 67 and no. 7 seed Anna-Lena Grönefeld in the qualifications in Sydney in three sets (5–7 in the third set) and the second round of Australian Open – after defeating unseeded Galina Voskoboeva with 6–4 6–4, she suffered a 6–1 6–4 loss to World no.28 Shahar Pe'er. March she reached the second rounds in Indian Wells and Miami after successfully overcoming the pre-qualification draws (winning 6–0 6–1 against no. 6 seeded Ayumi Morita in Indian Wells; she lost respectively to no. 23 seeded Kleybanova and Wozniacki after winning the first set in both matches). Pironkova made her first ITF Tour appearance of the year in the $25,000 Fort Walton Beach, where she reached the semifinals.
Tsvetana pironkova hot
Tsvetana pironkova
She then defeated the former Wimbledon finalist and number 11 seed Marion Bartoli 6–4, 6–4 in the fourth round. In the quarterfinals, Pironkova shocked second seed and five-time Wimbledon champion Venus Williams 6–2, 6–3 to become the first Bulgarian to reach a semi-final of a Grand Slam tournament since Manuela Maleeva (although Maleeva was playing under the Swiss banner) achieved this feat at the US Open in 1992 and 1993. Pironkova was ranked eighty places lower than Williams, making this defeat for Williams her most lopsided in her time playing at Wimbledon. 2011 was in Moorilla Hobart International where she lost to Peng Shuai of China in the first round. In the Australian Open Pironkova fell the in second round to Romanian Monica Niculescu. In the 2011 French Open Tsvetana was seeded 32nd. She lost to Gisela Dulko, the Argentine, in the second round. Pironkova entered Wimbledon as No. 32 seeded. In the third round Tsvetana defeated world No. 3 and second-seeded Vera Zvonareva 6–2 and 6–3, thus avenging her loss in the semifinals of the last year's Wimbledon.
She then defeated the former Wimbledon finalist and number 11 seed Marion Bartoli 6–4, 6–4 in the fourth round. In the quarterfinals, Pironkova shocked second seed and five-time Wimbledon champion Venus Williams 6–2, 6–3 to become the first Bulgarian to reach a semi-final of a Grand Slam tournament since Manuela Maleeva (although Maleeva was playing under the Swiss banner) achieved this feat at the US Open in 1992 and 1993. Pironkova was ranked eighty places lower than Williams, making this defeat for Williams her most lopsided in her time playing at Wimbledon. 2011 was in Moorilla Hobart International where she lost to Peng Shuai of China in the first round. In the Australian Open Pironkova fell the in second round to Romanian Monica Niculescu. In the 2011 French Open Tsvetana was seeded 32nd. She lost to Gisela Dulko, the Argentine, in the second round. Pironkova entered Wimbledon as No. 32 seeded. In the third round Tsvetana defeated world No. 3 and second-seeded Vera Zvonareva 6–2 and 6–3, thus avenging her loss in the semifinals of the last year's Wimbledon.