In a game full of chances for both sides, only Jeonbuk managed to find the back of the net when defender Cho Sung-hwan headed home in the 22nd minute after Eninho's corner was flicked on.

Jeonbuk striker Lee Dong-guk missed a number of chances while Dzenan Radoncic and Cho Dong-kun were all guilty of wasting opportunities in a pulsating match.

Seongnam's best effort came deep into injury time but striker Kim Kin-yong shot straight at goalkeeper Kwon Sun-tae when through on goal.

Jeonbuk, the 2009 K-League champions, now face Jeju United on Sunday in the penultimate round, with the winners taking on FC Seoul.

"We have achieved our first target in qualifying for the AFC Champions League," said Jeonbuk coach Choi Kang-hee.

"I am grateful to the players for giving this present to the fans.

"Now we have a tough game coming up at Jeju and we have to focus on that to the best of our ability."