Yokohama Marinos lost 1-0 to Omiya Ardija but retained leadership of the J.League on Saturday as nearest challengers Sanfrecce Hiroshima crashed to a 2-1 defeat at home to FC Tokyo.
Omiya's Daigo Watanabe scored in the 42nd minute to sink Marinos and end Ardija's run of eight consecutive defeats, cutting the league leaders' cushion to one point ahead of Urawa Red Diamonds, who moved into second with a 1-0 win over Albirex Niigata.
"Playing two games in a week is hard for both teams when it's as hot as this," said Urawa manager Mihailo Petrovic. "This game could have gone either way."
Defending champions Sanfrecce slipped to third, two points behind Urawa, after Takuji Yonemoto notched an 81st-minute winner for Tokyo.
Yuya Osako celebrated his call-up to the Japan squad for friendlies against Guatemala and Ghana with his sixth goal in four games as Kashima Antlers moved into fourth with a 3-1 win over Kashiwa Reysol.
Cerezo Osaka dropped to fifth after a 0-0 draw with Kawasaki Frontale, while Nagoya Grampus drew 1-1 with Sagan Tosu. Two late goals from Yasuhito Morishima were not enough to prevent bottom side Oita Trinita from losing 3-2 to Shimizu S-Pulse, while fellow strugglers Jubilo Iwata were pegged back by an 86th-minute Patric equaliser in a 1-1 draw with Ventforet Kofu.
In the day's other game, Shonan Bellmare beat Vegalta Sendai 3-2 but remained in the relegation zone five points from safety.