Olympic champion Chen had eased to straight-games wins in her first two matches of the tournament at the George R. Brown Convention Center, but Japan’s Miu Hirano provided a stern test.

Hirano, an Olympic team silver medallist at Tokyo 2020, claimed the second and third games of the contest to lead a tight match.

Chen secured the next two games to appear on the brink of victory, only for Hirano to force a decider by winning the sixth game 13-11.

Hirano’s challenge was ended by Chen in the decider, with the Chinese player able to pull away from her opponent to secure a 12-10, 13-15, 8-11, 11-8, 11-7, 11-13, 11-5 victory.

Japan’s Kasumi Ishikawa will face Chen in the last eight, after the sixth seed won 11-6, 11-9, 11-8, 11-8 against Bernadette Szőcs of Romania.

Sun had not dropped a game in her two singles matches at the World Championships and the trend appeared to be continuing when she took three-game lead against Puerto Rico’s Adriana Diaz.

An impressive response from Diaz saw her reduce the deficit to 3-2.

Sun eventually advanced to the quarter-finals in six games, winning 11-4, 11-8, 11-8, 9-11, 9-11, 11-4.

She will now face South Korea’s Suh Hyo-won, who was an 11-9, 11-9, 10-12, 11-9, 11-9 winner against Hong Kong’s Doo Hoi Kem.

Japan’s third seed Mima Ito secured her spot in the quarter-finals with an 11-9, 9-11, 11-7, 8-11, 12-10, 12-10 success against Thailand’s Suthasini Sawettabut.

China’s Wang Yidi will face Ito for a place in the semi-finals, after her 11-4, 11-6, 13-15, 11-6, 18-20, 11-5 triumph against Japan’s Hina Hayata.

Chen Xingtong and Wang Manyu complete the line-up for the last eight, guaranteeing China one representative in the semi-finals.

Chen beat Chinese Taipei’s Cheng I-ching 11-6, 11-13, 11-6, 11-5, 11-2, while Wang was an 11-5, 9-11, 11-7, 11-4, 11-5 winner over France’s Jia Nan Yuan.

World number one Fan Zhendong of China dropped his first games of the men’s singles event, but sealed a quarter-final spot.

Fan overcame Summer Youth Olympic Games gold medallist Wang Chuqin 11-5, 11-7, 11-13, 11-7, 8-11, 11-6 in an all-Chinese fourth-round tie.

Olympic silver medallist Fan faces another compatriot in the last eight, after Lin Gaoyuan secured an 11-6, 11-8, 12-10, 7-11, 11-7 win over Hong Kong’s Wong Chun Ting.

Liang Jingkun is the third and final Chinese player remaining in the draw, as he game through a gruelling fourth-round match to beat England’s Liam Pitchford 14-12, 11-6, 9-11, 11-6, 7-11, 3-11, 11-4.

Liang earned a meeting with third seed Hugo Calderano of Brazil, who recorded an 8-11, 11-6, 11-3, 13-11, 11-2 win over Slovenia’s Darko Jorgic.

Germany’s Timo Boll remains the highest-ranked player in the bottom half of the draw, after the eighth seed received a walkover against Slovakia’s Wang Yang.

The 40-year-old will now play the United States’ Kanak Jha, who beat Germany’s Ruwen Filus 11-8, 11-8, 3-11, 11-9, 11-2.

Sweden’s Truls Möregårdh emerged as the winner of a meeting between two unseeded players in the fourth round.

He came from three games down to secure a comeback 6-11, 13-15, 9-11, 11-8, 11-2, 11-5, 11-6 win over South Korea’s Lim Jong-hoon.

Möregårdh will face Nigeria’s Quadri Aruna, who won a thrilling tie 11-9, 5-11, 13-11, 5-11, 6-11, 11-8, 11-6 against Sweden’s Kristian Karlsson.

Aruna’s victory saw him become the first African player to reach the last eight of the World Table Tennis Championships.