Cerezo Osaka gave their J.League survival hopes a boost and simultaneously dented Urawa Reds' title charge with a 1-0 win on Saturday.
The Reds had been on a fine run of five wins from their previous six league matches, with the only blemish on their record in that period being a 4-4 draw at Tokyo.
A victory on Saturday would have seen them remain seven points clear at the top of the table, while Cerezo would have stayed in the relegation zone.
However, the result did not go to form as Cerezo snatched their second win from four games, after previously going 11 without victory.
Cerezo were dealt the blow of losing captain and Japan international Hotaru Yamaguchi for three months due to a knee injury in the build-up, but former Germany international forward Cacau stepped up.
The Brazil-born 33-year-old hammered a powerful right-footed effort past Shusaku Nishikawa with 21 minutes to go and the Reds were unable to produce a late fightback.
Making matters worse for the Reds, Kashima Antlers closed the gap at the top to four points with a stunning 5-0 dismantling of hosts Tokushima Vortis, who stay rock-bottom.
Goals in quick succession from Caio and Shoma Doi just before the break gave the visitors a healthy lead at half-time and they pressed home their advantage in the second half.
Caio added his second in the 58th minute and Yasushi Endo netted number four less than 60 seconds later, with the 26-year-old midfielder doubling his tally late on to complete a resounding triumph.
Kawasaki Frontale will be desperately disappointed not to have kept hold of second place after they drew 1-1 at home to Vegalta Sendai, who went into the match on the back of five consecutive league defeats.
Vegalta stay just outside the bottom three with that point, but Omiya Ardija's resurgence has them closing in on those above the drop zone, with Saturday's 2-1 defeat of fellow strugglers Shimizu S-Pulse representing their third win in four games.
In the fight for AFC Champions League spots, Gamba Osaka recorded an impressive 4-1 thrashing of fellow challengers Sagan Tosu, with Brazilian forward Patric inspiring them to victory with a hat-trick.
Tokyo's chances of a top-three finish received a boost with their 4-0 win at home to Kashiwa Reysol, while Albirex Niigata beat Nagoya Grampus - who saw Leandro Domingues sent off in stoppage time - 1-0 on the road to move into the safety of mid-table.
Elsewhere, Sanfrecce Hiroshima left it late to salvage a point at home to Vissel Kobe as Tsukasa Shiotani levelled in the 87th minute, and Ventforet Kofu claimed a 0-0 draw at Yokohama F. Marinos.