Beijing, China, 3 October 2017 | Leigh Rogers

Daria Gavrilova has advanced to the China Open third round.

The world No.22 was leading No.14-seed CoCo Vandeweghe 6-3 2-0 when the American retired with a spinal thoracic injury.

“Unfortunately CoCo did something with her back during the match, sometimes that happens, I’ve experienced it before,” Gavrilova said.

“It’s always hard to play someone who is not playing 100 per cent, so I felt like I did a good job on focusing on what I had to do and I thought I was returning really well. My game plan was pretty spot on and I still played really good tennis.”

Vandeweghe had started strongly, holding serve to love in the opening game and racing to a 3-1 lead.

It was after Gavrilova levelled it at 3-all that she noticed her opponent was hampered with injury.

“I was looking at the speed of her serves and I could tell she was not serving at 100 per cent, it dropped off by probably 30 km/h,” Gavrilova said.

“As her speed dropped off and so did her intensity, but she’s still a big hitter so I knew I had to keep it away from her and still work for it.”

After losing seven consecutive games, Vandeweghe retired.

Gavrilova next plays Czech world No.29 Barbora Strycova, a 6-4 6-2 winner over German Julia Goerges today.

“I think we are pretty similar players, both really good at being defensive,” Gavrilova said of the match-up. “She’s also good at the net and throws in everything she can. She’s cheeky, so I have to be ready.”

The pair played doubles together in Wuhan last week and Strycova won their only previous singles meeting in a three-set battle in August.

“I played her in Toronto and had a tough loss,” Gavrilova recalled. “I was in a really good position to win, up a set and a break, so I’m really looking forward to hopefully getting some revenge.”

Australians Sam Stosur and Ashleigh Barty play their second round matches tomorrow.

Barty faces world No.3 Elina Svitolina, while Stosur plays world No.8 Jelena Ostapenko.

Stosur revealed she was looking forward to the challenge of playing the reigning French Open champion.

“I’m quite impressed with how she (Ostapenko) has been able to back it up,” Stosur said. “Hats off to her, she’s stayed at it and I don’t feel like she’s dipped at all after coming off such a great win.

“To be honest this week I just came into it thinking ‘you know what, the result is going to be whatever it is going to be’ so I just really want to focus on what I’m trying to do and how I’m trying to play.”