South Korea Edge China 1-0 After Mass Brawl
Yoo celebrated his 111th cap with a 17th international goal, powering a header past goalkeeper Liu Yunfei from a Lee Eul-yong corner in first-half stoppage time in Saitama.
Lee was sent off on the hour for lashing out at Li Yi moments after clattering into the back of the China striker. The incident sparked a 22-man brawl in the centre of the pitch.
Striker Ahn Jung-hwan, who scored in the 3-1 win over Hong Kong on Thursday, almost made it 2-0 in the 72nd minute with a fierce shot from 20 meters that crashed against the upright.
Substitute Du Ping went close for China in injury time when his far-post header looped over goalkeeper Lee Woon-jae but Yoo arrived to clear, despite Chinese protests that the ball had crossed the line.
"I couldn't see from my position but I felt the referee should have given us a penalty, so it balanced out," said South Korea coach Humberto Coelho, who has come under fire after Asian Cup qualifying slip-ups against Vietnam and Oman. "We rushed things a bit in the first half but the players kept their shape well and turned it around superbly."
Japan-based Yoo had the only notable chance of a poor first half, curling a free-kick just wide in the 29th minute after a foul on Choi Yong-soo.