Pohang Steelers overcame second-placed Jeonbuk Motors, while Gwangju prevailed after trailing by three goals in the K-League on Saturday.
Goals from Hwang Jin-Sung, Ko Mu-Yeol and Lee Myeong-Ju handed Pohang a 3-2 win over Jeonbuk in the championship round at Steelyard Stadium.
Hwang and Ko scored inside the first 12 minutes before Jeonbuk forward Lee Dong-Gook, who scored in South Korea’s 2-1 loss to Australia on Wednesday, continued his run of good form with a goal three minutes later.
Lee Myeong-Ju found the net on the stroke of half-time, though the margin was reduced to one goal when Lee Dong-Gook struck again with seven minutes to go.
Jeonbuk pushed in search of an equaliser but fell short as Pohang provisionally climbed to third on the table.
Elsewhere, goals from Ahn Dong-Hyuk, Park Hee-Sung, Bogdan Milic and Joao Paulo earned Gwangju a remarkable 4-3 victory over Seongnam in the relegation round.
Seongnam led 3-0 after 30 minutes following a brace from Javier Reina brace and an Everton Santos goal.
But Gwangju responded in style, with Joao Paulo handing the visitors the most unlikely of leads in the 77th minute.
Daegu played host to Gangwon in a 2-2 draw in the day’s other relegation round clash.