Jeonnam Dragons were the beneficiaries as K.League leaders Pohang Steelers and Jeonbuk Motors both failed to win at home on Wednesday.
Defending champions Pohang had seen their lead at the top cut to two points after drawing 0-0 at Jeju United when the league resumed on Saturday after a mid-season break.
For the second match running, Hwang Sun-hong's men drew a blank in a stalemate with Seoul at the Steelyard Stadium.
That draw meant second-placed Jeonbuk Motors - who beat Busan I'Park on Saturday - had the chance to move level on points with Pohang.
However, they missed that opportunity after being held to a 1-1 by Jeju United, who could have gone second with a win.
Indeed, it appeared as though the visitors would leapfrog Jeonbuk after Song Jin-hyung opened the scoring six minutes before half-time.
Jeonbuk took a share of the spoils, however, when Kaio bagged his third goal of the campaign in the 79th minute.
Jeonnam subsequently moved to within three points of top spot in a 3-1 victory against Gyeongnam at the Gwangyang Stadium.
Kim In-han gave the visitors hope of snapping a nine-match winless run in the league, but Ahn Yong-woo and a goal in each half from Lee Jong-ho curtailed those hopes.
Another team to benefit were Suwon Bluewings, who climbed to fourth courtesy of a battling 3-2 win at home to Ulsan, despite a brace from Lee Yong for the visitors.
Elsewhere, rock-bottom Incheon United were pegged back in a 1-1 draw with Seongnam, while Sangju Sangmu defeated Busan I'Park 2-0.