A day after beating sixth seed Sofia Polcanova of Austria, Diaz won a dramatic round-of-16 match at the OMEGA Sports and Health Centre in Olomuoc against Sweden’s 36-year-old tenth seed Matilda Ekholm.

Diaz, who claimed gold medals at the recent Central American and Caribbean Games and the Pan American Junior Championships, eventually recorded an 11-5, 11-5, 11-4, 2-11, 3-11, 6-11, 11-5 victory.

The result saw her set up a meeting with top seed Kasumi Ishikawa, Japan’s multiple world and Olympic medallist.

It is the first time she has got so far at an ITTF World Tour women’s singles event.

Ishikawa reached the quarter-finals with an 11-7, 11-7, 7-11, 11-6, 9-11, 11-4 win over compatriot Honako Hashimoto. 

Japan's Miu Hirano, the number three seed, ended the progress of 16-year-old qualifier Miyu Nagasaki with an 11-5, 11-9, 12-10, 11-5 victory.

Germany’s top seed Dimitrij Ovtcharov, who began the year ranked world number one but had arrived in Olomuoc having failed to advance beyond the second round of the men’s singles in his four previous ITTF events, got back to business as usual in defeating South Korea’s Park Ganghyeon 11-3, 9-11, 11-5, 11-7, 11-9.

Ovtcharov’s quarter-final opponent will be Britain’s Liam Pitchford who, having beaten Rio 2016 champion Ma Long in the Bulgaria Open the previous week, earned victory over another Chinese player today in Zhang Yudong.

In the last women's singles match of the day, Japan's world number six Mima Ito beat China's Liu Gaoyang 11-9, 4-11, 11-8, 11-9, 11-5.

The tournament is due to continue tomorrow.