Reigning K-League champions FC Seoul were held to a 2-2 home draw against the Pohang Steelers on Saturday.
FC Seoul headed in to the opening day of the season full of confidence after thrashing Chinese Super League outfit Jiangsu Sainty 5-1 in the AFC Champions League on Wednesday.
And they took an early lead when Colombian midfielder Mauricio Molina netted after 30 minutes.
The Steelers produced an immediate response through Hwang Ji-Soo though as scores were levelled at the break.
Montenegrin Dejan Damjanovic scored 31 goals in the K-League last season and opened his account at the first opportunity just three minutes into the second half.
It looked like Damjanovic's goal would be enough to separate the two sides but Lee Myung-Ju had other ideas, bagging an equaliser with just six minutes to play.
Ulsan Hyundai top the table after a last-gasp 2-1 win against Daegu.
Han Seung-Yeob put Daegu in front after four minutes but goals in the last five minutes from Choi Bo-Kyung and Rafinha gave the hosts a dramatic victory.
The day's other match saw Jeju United defeat the Chunnam Dragons 1-0 thanks to a 31st-minute strike from Jair.