Ulsan fought back to see off Suwon Bluewings, while Seoul were also winners in Sunday's K League 1 action.
Junior Negao continued a flying start to the season with two goals as Ulsan produced a fine fightback to beat Suwon Bluewings 3-2 in Sunday's K League 1 action.
The home side appeared well in control of proceedings in front of an empty Suwon World Cup Stadium, with spectators still absent amid the coronavirus pandemic.
Ko Seung-beom and Sulejman Krpic scored either side of half-time to open up a two-goal lead before Junior Negao showed neat footwork and aimed a shot towards the bottom-left corner that No Dong-geon could not keep out to reduce the arrears.
Kim In-sung showed good strength to rifle home the equaliser just after the hour and Junior Negao – who scored twice in the opening-round 4-0 beating of Sangju Sangmu – completed the turnaround in the last minute with a long-range free-kick.
Han Chan-hee scored a 25-yard belter as Seoul recovered from an opening-round defeat to beat Gwangju 1-0.
Rounding out the action, Seongnam played out a goalless draw with Incheon United.