World number one Simona Halep is out of the China Open at the first hurdle, retiring with back trouble after losing the first set 6-1 to Ons Jabeur on Sunday. The Romanian's tournament lasted just 31 miserable minutes in Beijing and she never looked comfortable against the Tunisian qualifier. Halep, 27, suffered the back injury a week ago in Wuhan.

The top-ranked Halep's early departure is another blow to organisers in the Chinese capital, with Serena Williams missing from the women's draw and several big names also absent from the men's event. Holder Caroline Garcia is at least in action, but she survived a major scare before defeating wildcard Wang Yafan 7-6 (12/10), 6-7 (4/7), 6-3 to open the defence of her crown.