Jeonbuk Motors clinched their third title in six seasons after beating Jeju United 3-0 last week, but Sangju Sangmu and Seongnam are running out of time to preserve their top-tier status at the other end of the table.
Sangju are five points adrift of safety at the foot of the relegation round table with three matches remaining as they prepare to face third-placed Incheon United at Sungui Arena Park on Saturday.
Park Hang-seo's Sangju - without a win in four matches - are three points from the relegation play-off spot, which is occupied by Seongnam, while Gyeongnam are a further two points clear.
Sangju drew 1-1 at home to Seongnam last week after Juna Yang's 73rd-minute penalty salvaged a point and ended their run of three consecutive defeats.
Incheon have fared slightly better so far, with two draws enough for them to occupy third position.
Seongnam host Gyeongnam at Tancheon Sports Complex on Saturday, with the result going a long way in determining Sangju's fate.
Kim Hak-bum's Seongnam - seven-time K-League Classic champions and dual AFC Asian Champions League winners - have drawn back-to-back games since the competition split for the champion and relegation round.
Gyeongnam were 3-1 winners last week after Milos Stojanovic, Ahn Seong-bin and Song Su-young were all on target against Chunnam Dragons, who sit top of the relegation standings.
Chunnam are away at Busan I'Park in the other match.
At the other end of the standings, Seoul and Jeju are fighting to keep their Champions League qualification hopes alive.
With Jeonbuk (74 points) already assured of a Champions League berth, Suwon Bluewings (61 points) and Pohang Steelers (57 points) are poised to join them.
But Seoul (53 points) and Jeju (51 points) are waiting in the wings.
On Sunday, Seoul host sixth-placed Ulsan (48 points), who remain an outside chance of qualifying for the competition.
Jeju are in action on the same day, welcoming Suwon to Jeju World Cup Stadium.
In the other fixture, champions Jeonbuk and Pohang go head-to-head on Saturday.
