Jolyn Beer won in her first World Cup in Bangkok ©ISSF

First-time finalist Jolyn Beer sealed an unlikely victory at the International Shooting Sport Federation (ISSF) World Cup in Bangkok today after getting the better of world number one Snjezana Pejcic in the women's 50 metres three positions rifle.

The 21-year-old German performed terrifically under pressure in the final in the Thai capital, shooting consistently to win her first World Cup medal.

Despite a lack of experience, Beer finished on 455.9 points with Croatian Pejcic, an Olympic bronze medallist from Beijing 2008, left on 454.5 for silver.

Beer finished the kneeling section of the final in third place with 151.8 points, and then climbed up to second at the end of the prone series with 307.1 points, eventually overtaking Pejcic in the last fraction of the match.

“It’s amazing, it’s my first World Cup, and my first medal," said Beer.

"I am speechless.

“I was quite confident, anyway.

"The kneeling position is my weakest one.

"I told myself that if I managed to do well there, I was going to finish in style.

Guo Wenjun won the women's 10m air pistol title
Guo Wenjun won the women's 10m air pistol title ©ISSF

“The pressure kicked in at the last shot.

"I really wanted to beat Snjezana and win the match, but I was afraid to fire a bad shot.

"I zeroed-in, focusing on the technique, and I made it."

China’s Zhang Binbin claimed bronze with 444.0 points but the day was all about Beer, who doesn't even have a world ranking.

Elsewhere in Bangkok, at the first World Cup of the season, China's two-time Olympic gold medallist Guo Wenjun won the women's 10m air pistol competition.

She finished on 198.8 points to beat Chinese Taipei's Tien Chia Chen into silver after she managed 197.8.

Bronze went to China's Zhang Mengxue who scored 177.8.

“I have learned how to manage the stress of such situations through the years,” said Guo, the Olympic champion from Beijing 2008 and London 2012.

“As I am preparing for my third Olympics, I am trying to improve these psychological aspects of the game.

"You need good technical and physical preparation to compete, but a strong mind can make the difference in the fight for the medals.”

The World Cup continues tomorrow with the the men's 25m rapid fire pistol final.