South Korean shooter Kim Jang-mi failed to defend her 25m pistol gold medal at the Rio de Janeiro Olympics on Tuesday.

Kim finished ninth in the qualification rounds at Olympic Shooting Centre, unable to join the top eight that moved on to the final.

Kim shot 582 points -- 288 points in the precision portion and 294 points in the rapid fire portion. She was tied in total points with Heidi Diethelm Gerber of Switzerland and Ekaterina Korshunova of Russia, but they hit one more inner-10 than Kim with 21 apiece.

A second South Korean shooter, Hwang Seong-eun, finished in 18th.

Kim was only 20th after the precision stage. She then made a furious charge with a 98 in her first round of the rapid stage, and then a 100, before a 96 in the last round did her in.

Kim later acknowledged she was so nervous that "I was out of my mind" before taking her last shot.

"I don't even remember how I even managed to stay on my feet," she said. "I kept thinking it would all be over after this final shot. I tried not to be conscious of the pressure but I guess I couldn't quite do it. I should have won a medal for the team."

In London, South Korea led all nations with five medals -- three gold and two silver -- but remains without a medal four days into the Rio Games.

The shooting team had been counting on veteran Jin Jong-oh to start off the Rio Games with a gold in 10m air pistol on Saturday, but the defending champion could only finish in fifth.

Kim said she had become so used to performing after Jin had won a gold that when Jin couldn't pull it off this time, "It left a void in my heart."

The 23-year-old said she couldn't wait to get out of the range and go home.

"I still had fun," she added. "I started telling myself, '(The first medalist) doesn't have to be me.' I've been thinking about taking a trip after the Olympics, and that's what's kept me going this far."

Kim was one of the surprising gold medalists at the 2012 London Games, where she defeated the reigning Olympic champion, Chen Ying of China.

After London, Kim won a handful of International Shooting Sport Federation World Cup events, but has battled inconsistency in more recent years. (Yonhap)