Skating last before a packed house in Saitama, the Olympic silver medallists -- who narrowly missed gold at Pyeongchang after a mishap with Papadakis's costume in the short programme -- were awarded 88.42 points for their sultry routine.
"We're very pleased with this performance, because we skated really well. We love this programme, we love the choreography, we love working on it," Papadakis said.
Kagiyama enjoys perfect Grand Prix debut
Gabriella Papadakis and Guillaume Cizeron perform during the ice dance rhythm dance event
Image credit: Getty Images
There is a mandatory rhythm every year and it works for us every time more or less ... This time, the Tango theme was right up our alley, that is a theme that we love.
The pair have also been European champions every year since the 2014-2015 season but had to settle for Olympic silver last year when the clasp on Papadakis's costume came loose.
More than five points behind after a clean, sharp routine were Russians Victoria Sinitsina and Nikita Katsalapov, who were only fourth in the European Championships but clinched gold at the Russian nationals and silver at the Grand Prix Final.
"I am overwhelmed with emotions," said Sinitsina, after the two took 83.94 points.
I am trying to restrain myself and concentrate on our elements, our programme, but the emotions just burst out of me. It is a true joy to skate here.
In third place were fellow Russians Alexandra Stepanova and Ivan Bukin, fourth in the 2018 Grand Prix Final and second in the European Championships.
Bukin fell to the ice when their routine ended and mouthed "Wow!" when their score, a season's best 83.10, came up.
"We have made an attempt to fix the mistakes that we have made at the Russian nationals and the European Championship," he said.
"We wanted to skate heartily and enjoy our performance."
The World Championships continue at the arena north of Tokyo on Friday evening with the ladies free skate, where Olympic gold medallist Alina Zagitova has a commanding lead.
American skater Mariah Bell on Wednesday made contact with South Korean rival Lim Eun-soo in a practice, leaving the Korean with a cut leg and fanning memories of the Tonya Harding-Nancy Kerrigan affair in the 1990s.
But the International Skating Union (ISU) ruled that the incident was unintentional and Korean skating officials said the two might meet later on Friday so Bell could apologise.
Sakamoto takes the spoils in figure skating’s NHK Trophy
Kagiyama leads the way after day one of NHK Trophy action in Osaka