Incheon United were held to a 2-2 draw at Ulsan Hyundai as they tried to close the gap on K-League Classic leaders Pohang Steelers. Incheon twice had to come from behind after Kim Shinwook's brace for Ulsan.
Diogo Acosta got the first leveller after 67 minutes and Moon Sangyun made it 2-2 six minutes from time. The point left the second-placed visitors three points behind Pohang.
FC Seoul came from 2-0 down with 11 minutes to go to win 3-2 at home to Gangwon FC. Camilo Patrik opened the scoring and Adilson dos Santos' own goal put Gangwon two up at the break.
But Ko Yohan struck in the 79th and 85th minutes to draw Seoul level before Dejan Damjanovic got the winner three minutes from time.
Busan I'Park and Daejeon Citizen drew 1-1, Leandro Rodrigo equalising from the spot for Busan on the stroke of half-time to cancel out Kim Byungsuk's opener.