Zheng started 2005 by capturing her first WTA singles title at Hobart, after wins over Mariana Díaz Oliva, Shinobu Asagoe, Klara Koukalová, Li Na and Gisela Dulko.

She qualified for Dubai with wins over Sandra Kleinová, Maria-Elena Camerin and Virginia Ruano-Pascual, and went on to defeat Anabel Medina Garrigues in the main draw before succumbing to Lindsay Davenport.
Dulko gained her revenge in the quarterfinal at Estoril in April.

But Zheng remained in fine form, and reached her second WTA final at Rabat, Morocco in May, losing to Nuria Llagostera Vives after wins over Catalina Castaño, Maureen Drake and Tathiana Garbin, followed by a walk-over against Na Li who had to retire at 3–3 from an ankle sprain.

A three-set loss to Francesca Schiavone in the first round of the French Open prevented Zheng from defending her ranking points accrued there the previous year.
In August, she reached the second round at Los Angeles by again beating Shinobu Asagoe, the Canadian Open quarterfinal (with wins over María Emilia Salerni and Ai Sugiyama), and another quarterfinal at New Haven (after defeating Katarina Srebotnik and Émilie Loit in qualifying, and Jamea Jackson in the main draw, though she was assisted by entering the tournament with a first-round bye and as a lucky loser in the final round of qualifying to Jelena Kostanić).

At the end of the month, she advanced to the second round at the US Open by defeating Iveta Benešová.
Further first-round wins in September over María Vento-Kabchi (at Bali) and Jelena Janković (at Beijing) could not be consolidated on in subsequent rounds of the respective tournaments; but at Guangzhou, the last tournament she would play all year, she reached the semifinal with wins over Carly Gullickson, Jamea Jackson and Maria Kirilenko, before suffering her second loss of the year to Nuria Llagostera Vives.
This string of results lifted her to a career-high world ranking of 42 in early October 2005.
Zheng started 2005 by capturing her first WTA singles title at Hobart, after wins over Mariana Díaz Oliva, Shinobu Asagoe, Klara Koukalová, Li Na and Gisela Dulko.
She qualified for Dubai with wins over Sandra Kleinová, Maria-Elena Camerin and Virginia Ruano-Pascual, and went on to defeat Anabel Medina Garrigues in the main draw before succumbing to Lindsay Davenport. Dulko gained her revenge in the quarterfinal at Estoril in April.
But Zheng remained in fine form, and reached her second WTA final at Rabat, Morocco in May, losing to Nuria Llagostera Vives after wins over Catalina Castaño, Maureen Drake and Tathiana Garbin, followed by a walk-over against Na Li who had to retire at 3–3 from an ankle sprain.
A three-set loss to Francesca Schiavone in the first round of the French Open prevented Zheng from defending her ranking points accrued there the previous year. In August, she reached the second round at Los Angeles by again beating Shinobu Asagoe, the Canadian Open quarterfinal (with wins over María Emilia Salerni and Ai Sugiyama), and another quarterfinal at New Haven (after defeating Katarina Srebotnik and Émilie Loit in qualifying, and Jamea Jackson in the main draw, though she was assisted by entering the tournament with a first-round bye and as a lucky loser in the final round of qualifying to Jelena Kostanić).
At the end of the month, she advanced to the second round at the US Open by defeating Iveta Benešová. Further first-round wins in September over María Vento-Kabchi (at Bali) and Jelena Janković (at Beijing) could not be consolidated on in subsequent rounds of the respective tournaments; but at Guangzhou, the last tournament she would play all year, she reached the semifinal with wins over Carly Gullickson, Jamea Jackson and Maria Kirilenko, before suffering her second loss of the year to Nuria Llagostera Vives. This string of results lifted her to a career-high world ranking of 42 in early October 2005.
Zheng Jie