Urawa surrendered the lead late on in Wednesday's game at the Saitama Stadium 2002, and now sit five points adrift of Omiya at the top.
Mihailo Petrovic's men had grasped the advantage ten minutes from the end of normal time, as Yuki Abe converted from the penalty spot.
However, their hopes of increasing the pressure on their title rivals were dashed as Yoshiaki Ota struck in the 88th minute to earn the visitors a surprise point.
Elsewhere in the J.League, Sanfrecce Hiroshima failed to boost their chances of AFC Champions League qualification as they were held to a goalless draw by Kashiwa Reysol.