Hurt Sharapova retires at Shenzhen tennis

A thigh injury has forced fifth seed Maria Sharapova to retire from her quarter-final against top-ranked Aryna Sabalenka at China's Shenzhen Open tennis event.

Injury has forced 5th seed Maria Sharapova out of the Shenzhen Open tennis quarter-finals in China. (AAP)

Top seed Aryna Sabalenka has advanced to the semi-finals of the Shenzhen Open, with Maria Sharapova forced to retire due to an injury.

Fifth-seeded Sharapova was trailing 6-1 4-2 on Friday before she cited a left thigh injury.

Sabalenka was aggressive from the onset and built a 3-0 lead in the first set. She fired clean winners and extended her lead to a double break at 5-1 before closing out the set.

Sharapova received off-court medical treatment and came back strongly by holding her serve early in the second set.

But Sabalenka pulled off three-straight breaks of serve and took a 3-2 lead and, a game later, Sharapova retired.

Sabalenka will face Romanian qualifier Monica Niculescu or Wang Yafan of China in the semi-finals.