Two-time champion Lee Chong Wei fended off a spirited challenge from Boonsak Ponsana to win the men's singles title at the Chinese-boycotted Japan Open badminton tournament on Sunday.
The Malaysian top seed, the winner in Japan in 2007 and 2010, powered his way through to a 21-18, 21-18 victory over the Thai.
In the women's singles final, Tai Tzu-ying of Taiwan dashed any hopes of a title for Japan by beating Eriko Hirose 9-21, 21-9, 21-14.
South Korea's Kim Ki-Jung and Kim Sa-Rang defeated Koo Kien Keat and Tan Boon Heong 21-16, 21-19 to win the men's doubles, while Poon Lok-yan and Tse Ying-suet brought the first Japan title to Hong Kong.
They also dashed local hopes by beating Shizuka Matsuo and Mami Naito 21-17, 22-20.
Earlier in the day, Chan Peng Soon teamed up with Goh Liu Ying to beat Indonesia's Muhammad Rijal and Liliyana Natsir 21-12, 21-19 in the mixed doubles final.
"It was really a good match, but it was tough," said Lee, 29.
"This is my first tournament after the London Olympics. I'm very happy to start with this victory. I can put my disappointment behind me," said Lee, who lost to China's Lin Dan in the Olympic finals both in London and Beijing.
Lin, along with the rest of the Chinese team, missed the Tokyo tournament due to a boycott over a diplomatic wrangle about disputed islands in the East China Sea.
Lee hit a smash to take the first game. But neither could take a decisive lead at the start of the second game, which at one point was tied at 5-5.
Lee then jumped ahead 10-6 with several disguised overhead drop shots combined with a smash before powering his way to a commanding 20-15 lead.
Boonsak tenaciously saved three match points while trailing 18-20, but his jump smash went wide after a long rally on the next point, giving the 42-minute match to Lee.
The win saw Lee improve his record against Boonsak to 14 wins against two defeats.
Tai became the first player from Taiwan to win the women's singles title in the 30-year Japan Open history and only the second Taiwanese to win the title, following the mixed doubles by Chen Hung-ling and Cheng Wen-hsing last year.
"For me, it was my first title in the Superseries, so I'm really happy about it. She (Hirose) was too good in the first game, but I played better in the rest. I was able to win because I took the lead first in the final," Tai said.
"It was my first event after the Olympics. I got off to a good start to the following four years before the next Olympics. I was able to play without any pressure. That's why I won," added Tai, 18.