2005

In early January, she reached her first quarterfinal of the season in Hobart, defeating on her way Tatiana Perebiynis and Dinara Safina before losing to Iveta Benesova. Vaidisova picked up her first Grand Slam singles victory in her Australian Open début by reaching the third round with victories against Maria Vento-Kabchi and Jelena Kostanić, falling to top seed Lindsay Davenport. Following the tournament, she jumped in the ranking from No. 70 to No. 57.

In April, at the Family Circle Cup, she made her top 50 début at No.47 and reached her first career Tier I quarterfinals at Charleston, saving two match points in first round victory against qualifier Shahar Pe'er. She then posted her first top 10 victory over defending French Open champion Anastasia Myskina before also defeating Shinobu Asagoe in three sets. Vaidisova then fell to Patty Schnyder in the quarterfinals, making her top 40 début at No. 34 on April 18.

In May, Vaidisova reached her first Tier III final in Istanbul, losing to top seed Venus Williams in the championship match. She made her debut at Roland Garros, defeating Lucie safarova in the first round before falling in No. 22 seed Francesca Schiavone in the next round.

In August, she reached the quarterfinals at Toronto, defeating on her way lucky loser Shenay Perry, Nathalie Dechy and Hana Šromová before losing to Justine Henin-Hardenne. Her ranking continued to improve, jumping from No. 32 to No. 27 on August 22.

In September, at the 2005 US Open, she reached the fourth round for the first time at a Grand Slam event, defeating Květa Peschke, Zheng Jie and qualifier Ivana Lisjak before losing to Nadia Petrova.

Her ranking improved following the US Open, going from No. 28 to a career-high No. 23 on September 12. She captured her first title of 2005 (and third of career) at Seoul, defeating top seed Jelena Janković in the final without dropping a set during the week. She moved to career-best No. 21 at the start of October.

In that month, she captured her second straight Tour singles title as at Tokyo (Japan Open), winning when Tatiana Golovin retired while trailing 7-6(4) 3-2 due to a left achilles tendonitis in the final. On October 10, she made her top 20 début at No. 18 and extended her winning streak to 15 matches by winning her third consecutive Tour singles title and fifth of her career; she beat Conchita Martínez and Gisela Dulko en route to final, then overcame a 4-2 third-set deficit to defeat Nadia Petrova for the first time, 6-1 6-7(5) 7-5, in the final.

With the Seoul, Tokyo and Bangkok titles, Nicole Vaidisova became the first player since Lindsay Davenport in 2004 to win three titles in three weeks, and also became the sixth woman to win five Tour singles titles before her 17th birthday (after Tracy Austin, Andrea Jaeger, Monica Seles, Jennifer Capriati and Martina Hingis). On October 17, she improved her ranking from No. 18 to No. 17, another career-high.