The duo became the first Thai players to win the mixed doubles world championship title.
The only other Thai to win a world crown is women’s singles star Ratchanok Intanon in 2013, reports the Bangkok Post.
The world No.1 pair claimed their fifth successive title and eighth overall this year after beating arch-rivals Yuta Watanabe and Arisa Higashino of Japan 21-13, 21-14 in the 46-minute final at Palacios de los Deportes Carolina Marin in Huelva.
The Thais also made up for the disappointment from two years ago when they lost to then world No.1 Zheng Siwei and Huang Yaqiong of China in the final in Basel, Switzerland.
There was no tournament last year because of the coronavirus pandemic.
Dechapol and Sapsiree won the last three events of the 2021 World Tour season held in Bali, Indonesia, ahead of the World Championships.
They also won the Hylo Open in Germany before the Bali tournaments.
They started the year with three successive wins on home soil in the 2020 season-ending tournaments in January.
Watanabe and Higashino had been the Thais’ bogey team this year prior to their Bali successes. The Japanese pair had won all of their three match-ups, starting from the Tokyo Olympics quarter-finals, the Denmark Open final and the French Open semi-finals.
Dechapol and Sapsiree ended that losing streak in the Indonesia Open final and again beat the Tokyo Olympic bronze medallists in the World Tour Final.
Badminton boss Khunying Patama Leeswadtrakul congratulated the duo after their victory.
“I would like to congratulate Dechapol and Sapsiree for winning the world title,” said Patama.
“It is a historic achievement as both are Thailand’s first ever mixed doubles world champions and they have also won five successive tournaments.
“Both athletes are very disciplined as they were able to maintain their fitness level and standard throughout the three-month long overseas tour.
“They are a great example for a new generation of athletes to follow in their footsteps,” she added. “Their victory is also a New Year’s gift for Thai people.”
Meanwhile Akane Yamaguchi also became world champion for the first time after beating Tai Tzu-ying 21-14, 21-11 in the women’s singles title decider.
The Japanese second seed needed just 39 minutes to defeat Taiwanese top seed Tai, the Tokyo Olympics silver medallist, to claim gold.
In the women’s doubles final, top seeds Chen Qingchen and Jia Yifan of China defeated second seeds Lee So-Hee and Shin Seung-Chan of South Korea 21-16, 21-17 to claim the title.
Fifth seeds Takuro Hoki and Yugo Kobayashi of Japan, who reached their second straight men’s doubles final, were to face 16th-seeded Chinese He Jinting and Tan Qiang.
Also, Srikanth Kidambi of India was due to meet Loh Kean Yew of Singapore in the men’s singles decider.