Needing a win to stand any chance of reaching the Round of 16, the Sailors got just what they were looking for in the 26th minute when Song Ui-young latched onto the loose ball on the edge of the box and unleashed a powerful drive into the bottom corner.
But nine minutes after the restart, Daegu -- who also needed a win to make sure of their place in the last-16 -- when a hopeful left-wing delivery from Hong Chul sailed over a sea of players before being bundled home at the back post by Lee Keun-ho.
With the match evenly poised, proceedings were then halted with 15 minutes remaining due to a torrential downpour, which rendered the pitch unplayable.
Following a 30-minute delay, the game finally restarted and just shortly after -- with ten minutes remaining -- Daegu would go on to claim the victory through a Zeca penalty, after Amirul Adli had manhandled Kim Jin-hyuk inside the area while attempting to prevent him from getting to a high ball.
The defeat meant Sailors would finish the group stage third in Group F while Daegu advance to the Round of 16 for a second consecutive season as winners.
Although the win was not enough to see Urawa finish ahead of Daegu due to an inferior head-to-head record, they had already sealed their progress to the knockout round before Saturday by virtue of them being guaranteed one of the best runners-up spots at minimum.