World number one Halep could have been vulnerable to being overhauled in the rankings ahead of the opening grand slam event of the year in Melbourne this month had she lost in China.

But the Romanian recovered to beat Duan 3-6 6-1 6-2 on Wednesday and advance to the quarter-finals of the WTA International event. 

Halep will be desperate to end her wait for a first grand slam singles crown after losing in the final of the French Open last year, and the 26-year-old is now assured of being seeded first as she seeks to improve on quarter-final exits at Melbourne Park in 2014 and 2015.

Halep's compatriot Irina Camelia-Begu is also through in China after the fourth seed also staged a comeback to beat Ekaterina Alexandrova 4-6 6-1 6-2.

Katerina Siniakova, seeded sixth, accounted for Yafan Wang 7-5 6-3 and will face a fellow Czech in the last eight, Kristyna Pliskova having beaten Ana Bogdan 6-4 7-6 (7-3).