Kashima Antlers upset Gamba Osaka 1-0 on Sunday to complete the first round of a new J-League season which has already been overshadowed by China's mega-rich Super League.

After a raft of big-money moves by Chinese clubs in January's transfer window, the J-League returned to relatively little fanfare at the weekend, defending champions Sanfrecce Hiroshima beaten 1-0 at home by Kawasaki Frontale on Saturday.

Gamba Osaka, treble winners in 2014 and the current Emperor's Cup holders, failed to capitalise as they also crashed at home, substitute Yama Suzuki's 72nd-minute header settling a tepid affair which did little to get pulses racing.

Urawa Reds, Japan's best-supported club, opened their campaign with a 2-1 win at Kashiwa Reysol to complete a perfect week after a 2-0 midweek victory over Sydney FC in the Asian Champions League.

Part-owned by English club Manchester City, Yokohama F-Marinos slumped to a 1-0 home defeat by Vegalta Sendi while last season's second division champions Omiya Ardija upset FC Tokyo 1-0 in the Japanese capital.

In western Japan, Sagan Tosu beat Kyushu rivals Avispa Fukuoka 2-1 at home on the latter's return to the top flight.

The start of Japan's domestic football season slipped further under the radar with much of the local media focusing on Tokyo-based franchise the Sunwolves, who made their Super Rugby debut on Saturday.