Kento Momota defeated first seed Viktor Axelsen to secure a Japan Open final berth on Saturday, with the reigning world champion dominating an aggressive game 21-18, 21-11.
Momota's victory over the 24-year-old Danish giant will see him square off on Sunday against Thailand's Khosit Phetpradab, who beat South Korea's Lee Dong Keun 21-12, 21-16.
"It was really tough to endure a long rally while paying attention to sharp shots from Axelsen," Momota told TV Asahi after the match.
"I think I could win because I was able to chase the shuttlecock aggressively until the last minute," he added.
Momota last month became the first Japanese man to win the badminton World Championships, putting behind him a gambling scandal that threatened to ruin his career.
The 24-year-old was engulfed by controversy in 2016 when Japanese badminton chiefs suspended him for more than a year for visiting an illegal casino, denying him a place at the Rio Olympics.
Momota, number two in the world at the time, has been working his way back to the top ever since.
In women's singles, Olympic champion Carolina Marin sent China's Chen Yufei packing after beating the world number five 21-12, 21-13.
The Spaniard became the first woman to win three badminton world titles after an emphatic victory over PV Sindhu of India in Nanjing last month.
The all-action 25-year-old added the 2018 crown to her 2014 and 2015 titles, as well as the Olympic gold she won over the unlucky Sindhu at Rio 2016.
Marin will face on Sunday Japan's 2017 world champion Nozomi Okuhara, 23, who beat Aya Ohori also from Japan 21-12, 21-12.
