Gamba Osaka closed to within three points of J.League leaders Urawa Reds with a 2-1 win over Tokyo on Sunday.
Osaka's home victory, coupled with Urawa's 1-1 draw at third-placed Kashima Antlers, means they are in striking distance of the out-of-form table toppers.
Two goals in six minutes from Kotaro Omori and Yasuhito Endo early in the second half did the damage for Osaka, with Riku Matsuda's effort just after the hour mark proving nothing more than a consolation for Tokyo.
Urawa, meanwhile, were left to rue Marcio Richardes' early penalty miss as they were held a the Kashima Soccer Stadium.
Kawasaki Frontale slipped down a place to fourth after losing 2-1 at struggling Ventforet Kofu, who lifted themselves out of the relegation zone in the process, while Sagan Tosu's AFC Champions League hopes were dented after a shock 2-0 home defeat by Albirex Niigata.
Reigning champions Sanfrecce Hiroshima emerged 3-1 victors at Shimizu S-Pulse, who have dropped into the bottom three, and Yokohama F. Marinos - last season's runners-up - were held to a goalless stalemate by Cerezo Osaka.
Nagoya Grampus won 2-0 to inflict already-relegated Tokushima Vortis' 23rd league defeat of the season, while Vegalta Sendai and Omiya Ardija also remain in danger.
Their respective 2-1 losses to Kashiwa Reysol and Vissel Kobe leave them occupying the two places directly above the drop zone as the campaign nears its conclusion.