Tokushima, last season's second-tier play-off winners, looked to be coping well with the step up in quality until Kim Min-Woo and Hiroyuki Taniguchi scored just before the break.
Kei Ikeda struck early in the second half before Yohei Toyada's double, including one from the spot, wrapped up an easy triumph for Joon Jung-Hwan's men on Saturday.
It took until the 71st minute for the visitors to find the breakthrough, however, with Tsukasa Shiotani duly providing the winner for Hajime Moriyasu's charges.
Second division champions Gamba Osaka began life back in the top flight in a 1-0 defeat at home to Urawa Reds, while fellow promoted outfit Vissel Kobe fared better as they earned a 2-2 draw at Kawasaki Frontale thanks to Ryo Matsumura's injury-time leveller.
Davi got the ball rolling in the 11th minute, and the visitors entered half-time with a two-goal cushion courtesy of Yasushi Endo's strike.
Gen Shoji added a third shortly after the restart, while Davi's second of the match completed the comprehensive victory deep into injury time.
In other fixtures, Milivoje Novakovic snatched an 80th-minute winner for Shimizu S-Pulse in a 3-2 win at Nagoya, Albirex Niigata beat Vegalta Sendai 2-1 thanks to Roger Gaucho's late goal, and Kashiwa Reysol drew 1-1 with Tokyo.
