HONG KONG - Sun Yingsha and Lin Shidong sailed into the singles quarterfinals after claiming victories in Chinese derby at the World Table Tennis (WTT) Finals here on Thursday.

World No 1 Sun cruised past her teammate Wang Yidi 11-3, 11-9, 11-7, 11-7 in the women's singles, while 20-year-old Lin also swept Liang Jingkun 15-13, 11-3, 11-4, 11-9 to reach the men's singles last eight.

"We are familiar with each other. I hadn't expected to have a 4-0 win and just tried to focus on each point. I am satisfied with my mindset today and really enjoyed the match," said Sun, who will face Japan's Miyu Nagasaki on Friday.

"It is always not easy to compete with Liang," said Lin. "It was a tough match particularly in the first game today. I managed to control the pace and kept patience to seize the victory."

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China's Xiang Peng, Kuai Man also secured their berths in the men's and women's quarterfinals after winning over South Korea's An Jae-hyun and Japan's Hina Hayata, respectively.

In the mixed doubles, Wang Chuqin and Sun defeated their teammates Lin and Kuai 13-11, 12-10, 11-6, while Wong Chun-ting and Doo Hoi-kem of Hong Kong, China edged Indian pair Manush Shah and Diya Chitale 11-7, 11-3, 4-11, 10-12, 11-4.

On Friday, the singles quarterfinals will be on show, and the round-robin group competitions in the mixed doubles will continue at the WTT Finals.