Career
Starting in 2001, Nannan has enjoyed considerable success on the International Tennis Federation circuit, and occasionally qualified for Women's Tennis Association Tour events. She ended the year world-ranked 275. 2003 was a relatively poor year for Liu as a singles player until December, when she reached the quarter-final of a $50,000 tournament at Shenzhen with a clean run of five straight sets wins in qualifying and the main draw, only to cede victory to Zheng Jie by default.
Not even this run could stop her year-end ranking from falling outside the Top 400, at 401.
2004 was Liu"s most successful year to date as a singles player. She began it by winning a $10,000 tournament at Tampa, Florida, the fifth International Tennis Federation singles title of her career.
In June, she was the losing finalist to Li Na at a $25,000 tournament at Wulanhaote, and losing semi-finalist to Li Na at a $50,000 tournament at Beijing. In July, she came through qualifying to reach the semi-final at another $50,000 tournament, at Lexington, Kentucky, with wins over Shikha Uberoi, Rika Fujiwara and Aiko Nakamura.
In August, she defeated future star Jarmila Gajdošová in the first round of another $50,000 tournament at Louisville, then came through qualifying to the main draw of her first grand-slam tournament, the United States. Open, only to lose to Paola Suárez.
In September, she also qualified for the Women's Tennis Association tournament at Guangzhou, but lost in the first round after a close contest with Kristina Brandi. She ended the year world-ranked 170th, up 231 places year-on-year. In April, she reached the semi-final of a $75,000 tournament at Dothan, Alabama, losing to Varvara Lepchenko.
This brought up her world-ranking to a high point of 145.
She was destined to lose her opening match at four of the next five events she entered, the only exception being a $50,000 International Tennis Federation tournament at Beijing in June, where she reached the semi-final before conceding a walkover to Li Ting. Since losing to Lepchenko once more in the first round of qualifying for Los Angeles, early in August 2005, Liu has not played another singles match.
Her world ranking has therefore plummeted to 344th at the time of writing (March 4, 2006).