SOUTH KOREA, 12 Sept 2015, (AFP) - Lee birdied the par-five 18th at Woo Jeung Hills Country Club, and also the 17th, to surge ahead while Song, who was playing in the group behind and had been in control all day, scored a triple bogey on the last hole.
Lee, second in the Fujisankei Classic last weekend, shot a 68 to lead the OneAsia event on eight under.
Song was nine under stepping onto the 18th tee box but drove out of bounds for a 72 to fall back into a tie for second on six under with countrymen Hur In-Hoi and Lee Dong-Min.
Jeffress carded a 73 to slip back in a tie for fifth on five under.
"I don’t think anyone expected Song to finish like that. I am surprised to be in the lead," said Lee Kyung-Hoon.
"I played well though and finished strongly so I guess I have been rewarded for that. It will be a big day tomorrow and will be close," he added, referring to Sunday's fourth and final round.
Twenty-four-year-old Lee has emerged victorious once before as a professional golfer in the 2012 Sega Sammy Cup in Japan, while Song, also 24, is seeking his first win as a professional.
"I drove the ball poorly over the closing holes and was punished. I guess it is better to do that today as opposed tomorrow," Song said.
Leading scores (South Korea unless stated):
205 - Lee Kyung-Hoon
207 - Lee Dong-Min, Hur In-Hoi, Song Yong-Han
208 - Wang Jeung-Hun, Steve Jeffress (AUS)
209 - Kim Meen-Hee, Kim Seng-Yong, Park Jae-Bum
210 - Stephen Dartnall (AUS)