Tsukasa Umesaki, Shinzo Koroki, Ryota Moriwaki and Tomoya Ugajin were on target as Japan's best-supported side battered the visitors, while nearest rivals Sagan Tosu could only draw 2-2 at home to Shimizu S-Pulse.

Urawa, Japanese champions in 2006 and conquerors of Asia the year after, improved to 44 points from 22 games, three clear of Sagan, who salvaged a point thanks to an injury-time striker from substitute Ryota Hayasaka.

Omiya's "Squirrels" are without a win in 10 games and languish second from bottom of the first division with just 16 points.

Kashima Antlers stay third four points adrift of the leaders after being held 2-2 by visiting FC Tokyo while Kawasaki, who trail the Antlers on goal difference were lucky to escape with a 1-1 at Nagoya Grampus.

Gamba Osaka, who controversially had record caps holder Yasuhito Endo and free-scoring striker Takashi Usami left out of Javier Aguirre's first Japan squad named in midweek, spanked Albirex Niigata 5-0 at home.

Usami, who had smashed six goals in eight games since the World Cup break, unusually failed to get on the scoresheet, but it hardly mattered against a matador Albirex defence.

Yokohama F-Marinos ended a torrid week in which a banana-waving fan was banned for life for racial abuse and the club were slapped with a $48,000 fine with a 2-1 win at Vegalta Sendai for their third successive win.

Crisis club Tokushima Vortex lost again, this time 1-0 at home to champions Sanfrecce Hiroshima, their hopes of a miracle evaporating weekly after their 16th defeat of a brutal debut in the J-League top flight.