Sun Shengnan (; ; born 21 January 1987) is a Chinese former tennis player. Her highest WTA singles ranking is 216th, which she reached on 4 April 2011. Her career-high in doubles is 50th, which she reached on 17 September 2007. By March 2006, Sun had won two ITF singles titles and risen to No. 320 in the WTA rankings, and had earned herself a reputation as 'one to watch', having shown plenty of recent promise of further improvement in the preceding year. Career Sun Shengnan began competing on the ITF Circuit at the age of 15, in May 2002. Over the next few months, she won seven matches (mostly in qualifying draws) and lost just five. However, she did not compete again for a whole year after the beginning of August, and thus gained for herself only a lowly end-of-year foothold on the world ranking list at No. 1031. When August finally came around again in 2003, she returned to competition as a 16-year-old at ITF events; and that October she reached the quarterfinal of a $25k tournament at Beijing after being awarded a wildcard entry into the main draw, before losing to Yuka Yoshida. She finished the year with a 5–5 win–loss record after just a few events played. The record of her year-end ranking seems to have been lost by the WTA, but it was undoubtedly an improvement on her 2002 outcome thanks to the quarterfinal finish at Beijing. 2004 was another moderate year for Sun, as she won six matches and lost seven, her best finish again coming at October's $25k tournament at Beijing, where she repeated her previous year's performance in reaching the quarterfinal, this time losing to high-ranked countrywoman Zheng Jie. She finished the year world-ranked 588, which logically should have been similar to her previous year's finish. But it was to be in 2005 that the Chinese teenager would first break through to greater results, including two tournament wins. In February, she reached her career-first semifinal in the $10k tournament at Melilla. In April, she won the $10k event at Wuhan. Then in May, she won another $10k title at Ahmedabad. In August, she reached the final of a $25k fixture at Wuxi, losing to Miho Saeki of Japan. Then in September, she qualified for her first WTA Tour event at Guangzhou International Open with an impressive three-set victory over the young Croat