The 93rd minute penalty kick gave the visitors a lucky point after Gamba seemed to be on the way to second spot with their third win of the campaign, Yasuyuki Konno's 53rd minute strike being the difference between the teams until then.
It was Konno - celebrating his recall to the national team - who almost opened the scoring early on, with a header from a Yasuhito Endo corner, while, at the other end, both Shinzo Koroki and Tomoaki Makino hit the bar from distance for the visitors, although in both cases Gamba 'keeper Yosuke Fujigaya appeared to be in no trouble.
The goal came three minutes from the hour mark as Shu Kurata - also selected by Japan for the coming World Cup Qualifiers - advanced past his marker and slipped the ball out to the left wing. Oh Jaesuk ran into the space and sent a first-time cross over for Konno to rise above Makino and send home a bullet header to give Gamba the lead.
The home team then lost Yosuke Fujigaya to injury, the goalkeeping replacement for Masaaki Higashiguchi - out with a broken cheekbone - was himself replaced in the 73rd minute, as Tajiri came on to make his debut for Gamba.
A superb Konno was everywhere and he found himself on the left wing to latch onto a superb Endo pass in the 76th minute, his cross creating space for Ademilson to turn and shoot just wide.
Tajiri was then called into action on a Reds breakaway but was equal to the shot, and then saw Makino hit his right hand post with a header, but the 'keeper seemed to be going in the right direction to make the save if it the ball had been a few inches the right side of the woodwork! Then came the moment of good fortune for the away team as the ball hit hand as Kurata turned away from a Tomoya Ugajin blast, but the referee pointed to the spot and Urawa took home a point.
Team - Fujigaya (Tajiri, 73), Miura, Fabio, Kim, Oh (Ideguchi, 82), Hatsuse, Endo, Konno, Kurata, Ademilson (Akasaki, 89), Nagasawa
Goal: Yasukui KONNO, 57`