Heavyweights Viktor Axelsen and Kento Momota both won their matches at the Thomas and Uber Cup in Thailand on Tuesday.
The men's Thomas Cup and women's Uber Cup see the world's top nations compete in Bangkok's Impact Arena.
World number two Momota, who suffered a shock early exit from the Asia Championships last month, looked to be getting back into form with his 21-18, 21-11 victory over England's Toby Penty.
The 27-year-old Japanese player said he was "nervous but excited" before the match, his first this tournament, but that after the first game he settled into the competition and was able to better dominate the second.
Japan ended the overall bout against the English the victors, 5-0.
Elsewhere, Axelsen defeated France's Toma Junior Popov 21-8, 21-11, with the Danes' 5-0 win over the French clearing the way for their clash with China tomorrow.
Perhaps smarting from the women's early exit Monday, it was a better day for the Malaysian men's team, with the squad defeating the United States for the second Group D tie.
Malaysia will now take on Japan in the quarter-finals.
In the women's Uber Cup, Americans Lauren Lam and Kodi Tang Lee managed to snatch a 21-12, 17-21, 21-13 victory from Indian doubles pair Simran Singhi and Ritika Thaker -- but it was too little, too late, and India ended 4-1 up.
They will now advance to take on South Korea for Group D.
Elsewhere Japan's women, having nimbly dealt with the French threat 5-0, will meet Indonesia Wednesday to decide the Group A winners.