Young striker Yoo Chang-hyun did the damage with goals either side of the break to put the Steelers in control.

Macedonian marksman Stevica Ristic sealed the win just after the hour mark to hand in-form Pohang their sixth straight win in all competitions.

"The coach instructs us to attack and we managed to take our chances," said Yoo.

"I was nervous when I made my debut but, as I play more games, I am able to adapt more and more."

Korea Republic's other representative in the last eight of the continental competition, FC Seoul, were held to a goalless draw by Incheon United.

In the most entertaining match of the evening, Busan I'Park ended their recent run of indifferent results with a 3-2 win at home to Seongnam Ilhwa.

Brazilian playmaker Romulo grabbed the winner with three minutes remaining to set up an exciting second leg in two weeks' time.

Finally, Ulsan Hyundai Horang-I won 1-0 at Jeju United.