Park Tae-min's 74th minute goal was the difference, as Busan rebounded from their tough loss on Wednesday to defeat the military-scandal club Sangju 2-1 on Saturday evening.
Kim Chul-ho opened the scoring for Sangju in the 34th minute, off a rebound from keeper Lee Beom-young.
However, the I'Park responded four minutes later when Han Ji-ho equalized off a Han Sang-woon feed to tie the score at one before the half.
Midlfielder Yoon Dong-min fed a pass to Yang Dong-hyun, but his shot was stopped by keeper Kwon Son-tae, however the rebound went into a waiting Park Tae-min who made no mistake in securing the three points for I'Park.
The defense once again held Sangju at bay, while Lee Beom-young stopped 17 shots for the victory.
The fourth-place I'Park will host Suwon next Saturday night at 7 p.m. at the Asiad World Cup Stadium.