BANGKOK - Japan's women and men's teams swept opponents on the opening day of the Thomas and Uber badminton cups on Sunday, getting the nation's quest for both trophies off to a formidable start.

The women crushed Australia 5-0 in the morning while the men handily fended off Hong Kong 4-1. The world's 16 top nations compete for the men's Thomas Cup and women's Uber Cup every two years with matches comprising three singles and two doubles. While China dominated the sport for years, Japan has emerged with a shot at taking home both titles at this year's edition in Thailand.

Japan are favourites for the women's Uber Cup event and showed why when their Nozomi Okuhara, women's singles world champion, thrashed Australia's Louisa Ma 21-6, 21-6 in their Group A encounter. Doubles pair Misaki Matsutomo and Ayaka Takahashi then blew away Lee Yen Khoo and Ann-Louise Slee 21-3, 21-4 as the top seeds ran out comfortable winners. Buoyed by a loyal crowd on their home turf, Thailand's women also cruised past Germany 5-0 in Group B.

Meanwhile, Japan's men are aiming to repeat their 2014 Thomas Cup triumph but have a tough task against the likes of traditional powerhouses China and reigning champions Denmark, who became the first non-Asian winners in 2016. Japan are led by the former world number two Kento Momota, a 23-year-old dynamo who stunned China's Olympic gold-medallist Chen Long to win the Asia Championships last month.

On Sunday, he surged back from an early game loss to overpower Hong Kong's Ng Ka Long Angus 15-21, 21-16, 21-15 in their opening Group C encounter. "It's my great honour to be able to play here," Momota, who was barred from the Rio Olympics for illegal gambling, told reporters after his win. "I think my fast legwork, while playing patiently led to my victory," he said, adding that he would "play in a way that can amuse the audience more" in his next match.

His teammates went on to dominate their rivals save for a final match that saw Kazumasa Sakai felled by Hong Kong's Lee Cheuk Yiu 21-15, 21-13.

China's men routed Australia 5-0, while Indonesia and Taiwan similarly took all against Canada and Germany. Denmark, who will play on Monday, boast world number one Viktor Axelsen but will be missing doubles star Carsten Mogensen, who was been ruled out with sickness.

France's Ronan Labar predicted a wide-open event after his country got off the mark 4-1 against India in Group A of the men's competition. "Like always, a lot of Asian teams are strong and always tough, but I think in Europe and especially in France we are much more consistent than in past years," Labar told AFP after winning his doubles with Thom Gicquel 21-10, 21-12 against India's Arun George and Sanyam Shukla. "In general in the badminton world the level is more close now... It's really open," he added. "It can be one team winning and the next day it can be another one." The finals will be played next weekend.