Although the Japan Open showcased Chinese table tennis supremacy rather than Japan's rise, China's stars have a wary eye on the Tokyo 2020 Olympics hosts -- if their words are taken at face value.

Kasumi Ishikawa, Mima Ito and Asian champ Miu Hirano all crashed out before facing the eventual 16-year-old women's singles winner Sun Yingsha, while Rio bronze medalist Jun Mizutani was the only Japanese man to make the last four.

It was a sobering sight for many home fans, who had been buoyed by their nation's success at last month's worlds: a bronze by Hirano and quarterfinal appearance by 13-year-old Tomokazu Harimoto in men's singles.

But Chinese players left with praise for Japan, a country cementing its place as their closest rival.

"Japan has been our main rival for the past few years now," men's singles winner and world No. 1 Ma Long said. "They have been in the finals with us at team events, including the Rio Games, and are a really strong team."

"We see them as a threat, as a source of pressure. They are young filled with potential."

While much of the pre-tournament talk was about Japan's newest young guns, Hirano and Harimoto, the event at Tokyo Metropolitan Gymnasium, however saw a new Chinese star, Sun, top the podium. The teenager played down her own feat, while talking up a potential future rivalry with Ito, 16, and Hirano, 17.

"I know both players, they have some really strong points. I believe they are ahead of me in terms of ability," Sun said. "I have something in common with Hirano, we have a similar height and both of us play at pace."

World No. 2 Fan Zhendong, the beaten men's finalist, said more World Tour matches with Japanese players are indicative of the progress they are making.

"I've played (Koki) Niwa and (Jun) Mizutani at the world championships as well as here. I had a fierce game then and I feel their growth," he said.

And even for someone with Ma's pedigree, the rise of Harimoto, whose parents are from China, was too big to miss.

"I'd met him when he was in the sixth grade. He had been playing in the junior world tour since and has grown in height the past two years, as well as in technique," Ma said. "I haven't played him many times, but I'm paying attention."

But with someone like Ma spearheading the sport's strongest nation, Japan and other potential challengers must feel their task is nearly insurmountable.

"There were Olympic gold medalists and world champions before me whom I admired. But we all start from zero and stand on the same line at a match," Ma said.

"I've never thought of myself as an obstacle before the young Chinese players...I compete with the young players. That's one reason why I can maintain my edge."