Premier League stars Son Heung-min and Ki Sung-yueng struggled to make a decisive impact as Northern Ireland pounced to upset South Korea.
Northern Ireland came from behind to defeat South Korea 2-1 and inflict an early blow in the visitors' preparations for the World Cup finals.
Kwon Chang-hoon opened the scoring in the seventh minute for the Asian heavyweights, Northern Ireland equalising by forcing a Kim Min-jae own goal from a clever set-piece 13 minutes later.
South Korea, led by Tottenham star Son Heung-min and with Swansea City midfielder Ki Sung-yueng wearing the captain's armband, controlled possession and pressed in search of a second goal after the break.