efe-epaGuangzhou, China

Home favorite Chen Yufei of China on Friday bowed out of the ongoing BWF World Tour Finals in Guangzhou after retiring hurt from her women's single match against Japan's Nozomi Okuhara.

Former world champion Okuhara was leading 5-4 in the first game when Chen pulled out due to a right-ankle injury.

Okuhara and Thailand's Ratchanok Intanon progressed to the semifinals from Group B due to Chen's retirement, which altered the results.

According to competition rules, if illness or injury prevents a player from competing in all the group matches, all the results of that player in the group are deleted.

Intanon had beaten Chen in her first match of the tournament on Wednesday and then lost to Okuhara the next day, while Okuhara had beaten Michelle Li of Canada - the fourth player in the group - on Wednesday.

The top two players from the two groups are set to qualify for the semifinals, after which a knockout draw will be held.

The BWF World Tour Finals is one of badminton's most prestigious tournaments and the year's biggest event in terms of its prize money ($1.5 million).