Had the tennis coach at Catholic Junior College cast a more forgiving eye at Teo Shun Xie's forehand, next month's Olympic Games might never have been in the national shooter's cross-hairs.

Tennis had, after all, been her first love. As a child, she had watched her mother play the sport - and Teo took lessons at Raffles Town Club when she was about 15. But it also proved a major letdown for her when she failed to make the college team.

Disappointed, she began shooting on a whim and for company - a bunch of her classmates had signed up - and a decade later, the relationship is still thriving.

The 28-year-old will compete in two events (10m air pistol and 25m pistol) in Rio and is one of only two shooters Singapore is sending to the Summer Games.

Teo is also the reigning Commonwealth Games and SEA Games champion in the 10m air pistol, her pet event.

Not bad for someone who was not much of a sharpshooter in her secondary school days and failed her National Police Cadet Corps marksmanship test.

Her passion for shooting was a slow burner, she admitted.

"It took a while for me to really like this sport. I did fail the marksmanship test, so the idea of going back to it (in CJC) was..." she added, her scrunched face completing that thought.

Nevertheless, it was a journey of discovery for the Institute of Molecular and Cell Biology research officer.

She said: "In tennis, you have to beat your opponent but in shooting, it's only yourself... everything appears the same but you can't replicate the same shot time and time again.

"You're always learning new things about yourself; how you can control your body to go against its normal bodily reactions, how during competitions everyone gets nervous but you can switch that off and go against your fight-or-flight response."

Her trigger moment came when she was invited in 2006 to join the national team, where the structured training sessions and working with a professional coach provided the ideal environment for someone with her methodical personality to excel.

She said: "I could see my scores improving, my grouping getting tighter. This is a sport not dependent on your physical attributes. It's about your level of skill."

That standard kept rising. Before the 2009 SEA Games in Laos, she recorded a new personal best - a world-class score of 384 in the 10m air pistol. That breakthrough - she does not remember clearing 380 prior to that - deepened her attraction.

A vital hurdle had been cleared. She said: "That's when you continue to push yourself harder."

It is this drive that sees Teo travel three times a week after work from Buona Vista to Safra Yishun for 10m practice. On weekends, she is at the National Shooting Centre in Choa Chu Kang for the longer event.

Team-mate Jasmine Ser, who will compete in the 10m air rifle and 50m three-positions in Brazil, was impressed not just with Teo's work ethic but also admired her zen-like approach to those Kipling impostors, triumph and disaster.

A Commonwealth Games champion herself, Ser said: "Her character is easy-going and she can treat things very lightly. She's very patient and calm, always hard-working... These are the things that stand out and what make her successful."

Teo's performance at the ISSF World Cup leg in Rio de Janeiro in April, when she bagged a bronze in the 10m event, was world-class.

Despite the humidity, perspiration and sweaty palms, the Singaporean, in her first World Cup final, finished ahead of China's Guo Wenjun, a two-time Olympic champion, and South Korean Kim Jang Mi, the 25m pistol gold medallist in London 2012.

That medal may not mean one is guaranteed at the Olympics, stressed Teo. "But it's definitely confirmation that everything I'm doing, my training, is moving me in the right direction."

Buoyed by that memory of standing on the podium, she will return to Brazil in her hand-me-down shooting boots, carrying a Steyr LP10E pistol with the Olympic rings etched into its wooden grip.

"Back then, it was something to aspire towards," said Teo, who had the carving done in 2013 when she competed at the World Cup leg in Granada, Spain.

In less than a fortnight, she will enter Rio's National Shooting Centre not only as an Olympian but one armed with the self-belief that a medal is within her grasp.