Sun led South Korea to its third-straight gold medal at the Asian Games in Jakarta, but the team's uninspiring performance fueled public anger.

"We returned home with a gold medal, but we couldn't really celebrate," Sun said in his statement to media. "I felt miserable as a national team manager who couldn't protect the players' pride and honor. That's when I made up my mind."

After the Asian Games, a civic group filed a report to the Anti-Corruption and Civil Rights Commission, the state anti-corruption watchdog, alleging that Sun violated the anti-graft law by picking underperforming players. He was then summoned to a parliamentary audit session by lawmakers.

Critics said Sun chose some players just to help them get their exemptions from military service, since South Korea, as the only fully professional team at the Asian Games, was virtually guaranteed to win the gold medal. Healthy South Korean men are required to serve about two years in the military, but athletes who win an Asian Games gold medal are exempt from conscription.

Sun said he was also hurt by the parliamentary audit.

"At the parliamentary audit, a lawmaker said our victory (at the Asian Games) wasn't really a difficult task and that comment also helped me to make my decision," he said. "A manager has infinite responsibility and I've never tried to dodge that. But manager's authority on roster selection and game operation need to be respected and should be independent."

Sun added that sports and politics should be always separate and that he hopes he is the last coach to be summoned to a parliamentary audit.

"I heard that it was the first time in sports history that a national team manager attended a parliamentary audit session as a witness," he said. "Sports should not be consumed for political reasons and I hope my case is the last one."

Sun apparently expressed disappointment in Chung, who made controversial remarks during a parliamentary audit. Chung then said he's opposed to having a full-time manager for the national team and criticized Sun for scouting players by watching KBO games on television, instead of going to ballparks.

"Now, I know what the commissioner thinks about full-time national team manager, and I hope me stepping down is consistent with his belief," Sun said.

Sun, the former KBO MVP-winning pitcher, became South Korea's first full-time national team manager last July. He first managed South Korea at the 2017 Asia Professional Baseball Championship -- a tournament also featuring Japan and Chinese Taipei that was open only to players under 24 -- followed by the Asian Games in Indonesia this summer.

Sun said he had intended to announce his decision early, but waited until the KBO championship series was over.

South Korea's next big event is the 2019 Premier 12, which will double as a qualifying event for the 2020 Tokyo Olympics. Sun was contracted until Tokyo 2020, should South Korea qualify for the Olympic Games.

The KBO was in shock as it didn't expect Sun's resignation and emphasized having tried to keep him in the post.

"The commissioner, me and other KBO employees all did not expect Sun's resignation," Chang Yoon-ho, KBO's secretary general, said. "The commissioner even grabbed Sun as he left the office and asked him to lead the team until the Tokyo Olympics. We've had no time to think about a new manager." (Yonhap)