Yoo Yeon-seong
Ko started to get the attention of the World and Korean badminton when he won the bronze medal at the 2010 World Championships partnered with Ha Jung-eun. Competed in the men's doubles with Yoo Yeon-seong, Ko have achieved several milestones, including won the silver medals at the 2009 Asian and 2011 World Championships, reached a career high as world number 2 at the BWF world ranking. Ko and Yoo ended their partnerships after participating in 2012 London Olympics. Ko then topped the men's doubles BWF world ranking partnered with Lee Yong-dae in May 2013. Ko and Lee were a gold medalists at the 2013 Asian Championships and Summer Universiade.