NANJING - Japan's Kento Momota, who last year completed a lengthy ban for illegal gambling, is within touching distance of redemption after surging into the final of the badminton World Championships on Saturday.

He will play China's Shi Yuqi in Sunday's Nanjing showpiece, which promises to be a thrilling showdown between two of badminton's rising stars. The women's final tees up Spain's Olympic champion Carolina Marin against P.V. Sindhu of India -- a re-run of the 2016 Rio Games final.

The 23-year-old Momota's highly promising career descended into controversy in 2016 when Japanese badminton chiefs suspended him for more than a year for visiting an illicit casino, denying him a place at Rio. Momota has been working his way back to the top of badminton ever since and the world-ranked seven is currently in the form of his life.

He faced a dangerous challenge in his semi-final from Liew Daren, the unseeded Malaysian who was the tournament giant-killer. Liew surged into a 5-0 lead in the first game but the explosive Momota woke up to seize the initiative -- and ultimately the match -- in style, 21-16, 21-5.

Momota, the first Japanese man to reach a world championship final, put his sluggish start down to nerves. "He was very fast and I did not adapt myself well to his pace," he said, vowing not to repeat that in the final. "Shi is a world-class player and all-rounder so it will be a very tough game. But I will be tenacious and the lesson I will take from today is that I need to take the initiative and not be passive." Liew, who became Malaysia's standard-bearer in Nanjing in the absence of the ill world number two Lee Chong Wei, suffered a foot injury in his quarter-final and said it failed to fully heal. "But I never expected this (reaching the semi-finals) so really happy," he said. Shi equally comfortably beat Chen Long to race into the final and confirm his newfound status as China's best player. The 22-year-old defeated Chinese legend Lin Dan on the way to the last four and has now claimed the scalp of Olympic champion Chen, who was chasing a third world title.

The brilliantly agile Shi taught Chen, 29, something of a lesson with a comprehensive 21-11, 21-17 victory.

Shi has a long way to go to emulate his more seasoned compatriots, but defeating Chen for just the second time was more evidence of a changing of the guard in Chinese men's badminton. Marin, a two-time world champion, was a game down to He Bingjiao when the Chinese took a heavy fall at the start of the second.

The sound of her hitting the floor was clearly audible in the arena and she was prone for several seconds. She gingerly picked herself up -- to roars from the crowd -- but He was never the same after that, Marin winning 13-21, 21-16, 21-13 as her foe's game collapsed.

The sixth seed He said: "The fall was painful. I was not injured, but I was distracted by the pain."

Sindhu booked a revenge mission against Marin after roaring back in a thrilling second game to defeat Japan's Akane Yamaguchi 21-16, 24-22. "I hope this time will be a better result than last time," the third seed said.