Ishikawa, seeded sixth, was beaten 6-11, 5-11, 8-11, 5-11 by home player Chen Xingtong on day two of the ITTF World Tour Platinum event at the Chinese city’s Bao'an Stadium.

Chen’s reward is a last-eight meeting with third-seeded compatriot Chen Meng, who defeated North Korea’s Kim Song-i 11-6, 11-8, 11-6, 11-5.

Four other Chinese players are through to the quarter-finals, comprising top seed Ding Ning, second seed Zhu Yuling, fourth seed and defending champion Wang Manyu, and fifth seed Liu Shiwen.

Wang and world champion Liu will face each other in the last eight after the former overcame Chinese Taipei’s Chen Szu-Yu 11-5, 12-14, 14-12, 11-8, 11-5 and the latter claimed an 11-8, 11-5, 11-7, 11-5 win over Austria’s Sofia Polcanova.

Ding beat Japan’s Miu Hirano 11-9, 11-3, 11-6, 11-7 today, while Zhu defeated fellow countrywoman Qian Tianyi 11-8, 11-8, 11-5, 11-6.

Next up for Ding is seventh-seeded Japanese Mima Ito, an 11-6, 11-8, 14-12, 11-9 victor at the expense of Singapore’s Feng Tianwei.

Standing between Zhu and the semi-finals is eighth-seeded Taiwanese Cheng I-Ching, who overcame Romania’s Bernadette Szőcs 14-12, 9-11, 11-7, 11-3, 13-15, 11-8.

In the men's singles event, top seed Fan Zhendong remains on course to triumph after beating Slovakia's Lubomir Pistej 11-7, 7-11, 11-0, 11-8, 12-10.

He faces a stern test in the quarter-finals, however, with fellow Chinese Ma Long, the seven-time defending champion and three-time reigning world champion, his next opponent.

Ma thrashed eighth seed Koki Niwa of Japan 11-4, 11-5, 11-5, 11-2 in the round of 16.

Second seed Xu Xin of China is also through to the last eight thanks to a comfortable victory over Japan's Jun Mizutani - 11-4, 11-8, 11-6, 11-7.

Germany's Timo Boll, the fifth seed, will be Xu's opponent in the quarter-finals following a hard-fought 11-8, 8-11, 11-9, 13-15, 8-11, 12-10, 11-8 win over China's Yu Ziyang.

The two other last-eight ties pit third-seeded Chinese Lin Gaoyuan against compatriot Liang Jingkun and fourth seed Tomokazu Harimoto against Hong Kong's Wong Chun Ting.

Lin edged Germany's Dimitrij Ovtcharov 9-11, 11-8, 9-11, 9-11, 11-9, 12-10, 17-15, while Liang downed seventh seed Hugo Calderano of Brazil 8-11, 11-8, 9-11, 11-9, 11-4, 11-6.

Wong advanced to the quarter-finals by defeating France's Simon Gauzy 11-4, 9-11, 11-7, 11-6, 11-9 before Harimoto overcame England's Liam Pitchford 11-8, 11-9, 11-8, 11-8.

Action in Shenzhen is due to continue tomorrow.

All eight quarter-finals will be held across the men's and women's singles events.