Dane Axelsen took to the court first against Thailand's Kunlavut Vitidsarn and blitzed his way through the first game, taking it 21-5.

The Tokyo 2020 gold medallist faced a tougher challenge in the second game but still managed to prevail 21-16.

The triumph means the 28-year-old has added to his victory at the Glasgow 2017 World Badminton Championships and extended his unbeaten streak to 37 matches.

Axelsen now simultaneously holds the Olympic, World Championship, World Tour crowns, and the last three Super 1000 titles on the Badminton World Federation World Tour.

"I'm really happy about how I managed to control and to deal with everything in there," said Axelsen.

"Obviously, I was also the favourite and there was a lot of pressure on me.

"But I managed to perform under this pressure, and I'm really proud of myself."

Reigning champion Yamaguchi of Japan was next up on court against Chinese Olympic gold medallist Chen Yufei.

She got off to a perfect start and took the first game lead 21-12.

Chen rapidly levelled the score as she picked up a 21-10 win in the second game, sending the final to a decider.

An early seven-point streak from Yamaguchi proved vital in the third game as the Chinese shuttler could not bring the deficit to less than four points. 

The world number one became the first Japanese player to win back-to-back women's singles Badminton World Championships, closing out game three 21-14.

"I'm happy to get the best result possible at the world championships in Japan," said Yamaguchi, as reported by Kyodo News.

"It was a positive that I could enjoy playing despite the nerves and pressure."

Malaysia's Aaron Chia and Soh Wooi Yik won the first gold of the day as they beat Indonesia's Mohammad Ahsan and Hendra Setiawan 21-19, 21-14 after 40 minutes in the men's doubles final.

Soh and Chia are Malaysia's first-ever badminton world champions.

Chinese top seeds Chen Qingchen and Jia Yifan won the women's doubles tournament in straight games against South Korean duo Kim So-yeong and Kong Hee-yong 22-20, 21-14.

Zheng Siwei and Huang Yaqiong were the second Chinese champions of the day as they beat Yuta Watanabe and Arisa Higashino of Japan 21-13, 21-16 to secure mixed doubles glory.