Third-placed Suwon went into the weekend six points adrift of Pohang in second and seven behind leaders Jeonbuk Motors.
However, a combination of a thrilling 2-1 win over Pohang and Jeonbuk unexpectedly dropping two points in a 0-0 stalemate at home to Seoul means Seo Jung-won's side have renewed hope of heading into the Championship Round as regular season table-toppers.
Pohang looked to be on course for a valuable away victory at the Suwon World Cup Stadium when Ryu Chang-hyun put them ahead just before half-time, and they remained in front with just four minutes to play.
However, Suwon's Brazilian forward Roger levelled matters in the 86th minute, before Yeom Ki-hun popped up at the death to seal a remarkable turnaround.
In further good news for Suwon on Sunday, fourth-placed Jeju United also dropped points by being held to a 1-1 draw at Seongnam.
Things could have been worse for Jeju, too, as they required an injury-time penalty from Hugo Droguett to rescue a point after Server Djeparov had put Seongnam ahead from the spot early in the second half.
Ulsan, who sit just outside the top six, also came from behind to claim a point, as Baek Ji-hoon equalised Gu Bon-sang's opener for Incheon United at the Munsu Cup Stadium.
At the other end of the table, Busan I'Park replaced Gyeongnam at the bottom as they were beaten 2-1 at Jeonnam Dragons and Lee Cha-man's team edged Sangju Sangmu 1-0 at home.
