Martina Veloso's face during conversation tells brilliant lies. It tells you nothing about who she is inside. It's a young face, fresh, smiling, unthreatening. It could be a face you might find on a choir girl, but really it belongs to a champion.

Veloso is 1.6m tall, 18 years old, carries a fuschia-coloured rifle and, in competition, wears toughness like a perfume.

Last week, I hear a story about a team-mate who watched Veloso walk into the 10m air rifle final at last month's Commonwealth Games and said: "There is an aura around her. Like she is telling everyone, 'I'm going to own this.'"

In that final, with two people left, an Indian shooter equals Veloso's score on the very last shot with a 10.9, the highest possible score in shooting, akin to hitting the nib of a pen from 10m. Now there's a shoot-off and Veloso has to be rattled because her rival just met perfection and there's a gold medal on the line, but instead, she tells herself: "You've got this. It's not over yet."

This is where performers want to be, at this scary place of opportunity, perched between masterpiece and misstep, where they must dig deep to discover new limits. To compete, for them, is to be alive. Says Veloso: "I put my game face on" and it's not a look as much as an attitude.

Fifty-nine Singapore athletes went to the Gold Coast, five golds were won in total, two by Veloso in the 10m air rifle shoot-off and then the 50m rifle prone. She is tougher than you think in a sport that's tougher than you can imagine.

You can't break a racket in shooting or spit at a referee and so you have to cage your emotion. You have no control over other shooters, you can't affect them like a tennis player imposing his skill on a rival, and so every day, you have to chase perfection because there's a good chance one of them might find it.

This requires steel, which you can't always see, but it's there, at the athletes' core, pushing them on, like the bleeding boxer still coming forward or the tired runner telling himself he has more kilometres left.

Veloso learnt synchronised swimming and ballet as a kid, started taekwondo at five and switched from kicking people to firing guns at 11. Mess with her at your own risk.

Much like musicians who know the pressure of flawlessness - a wrong note is the cousin of an inaccurate bullet - it's a steel forged in the furnace of practice. Slowly, deliberately. Painfully.

"I train five days a week," Veloso says, "and up to two sessions a day. And I'm a full-time student at Nanyang Polytechnic."

She travels overseas to compete, studies, trains, takes public transport from her HDB flat in Woodlands, sometimes dozes off in class because she's so exhausted, but this is who she is, a child of "101 per cent".

I ask her if she cries if she shoots badly and she says it happens and then adds: "Even sometimes during practice. It's very, very tough because you're so fatigued and the requirements keep getting higher." And her requirement is simply brutal: Be better, better, better, than herself and the world.

"You have to endure," she says, and this is how she lives more, by pushing herself, by believing in her talent, by expressing herself through her art. Her chase is not merely for a medal, but for some elusive mastery over her craft.

There is a lovely candour to her when she says: "I am not very smart in class but I give my best. I like sports because I can show I am equally capable." There is a life beyond law and medicine and it can be found even in earning a degree in accuracy.

Veloso is tiny, absent of brawn and not given to a spitting aggressiveness. She's proof that toughness isn't just muscle - it's character. It isn't in-your-face, but the equanimity with which you face life.

And so she stands, as still as a birdwatcher, firing 60 consecutive pellets into a .5mm bullseye with the knowledge that a single hesitation, a momentary tremor, a passing breeze will mean a painful 9.2 and not a required 10.5. Only millimetres separate both scores but these are the mad margins of success in a lonely sport. "You are your own companion out there," she says.

Veloso at work reminds me of a person who can write religious verses on a grain of rice. A child of patient precision which her engineer father would approve of. But calm, the foundation of most great feats, is never easily found.

At the Commonwealth Games, she hummed to herself during finals and deleted her Facebook and Instagram apps from her phone before competition. She did visualisation exercises with her coach, listening to worship music and imagining herself in the mountains. And, for five to 10 minutes before her event, she did what a modern, meditative monk might do: Zen colouring.

Athletes often get mistaken for some superhuman species with magical powers but, really, it's their humanness that makes them most interesting. Behind all victories lies a vulnerable being like us. They might overcome the world, or the Commonwealth, but first, they learn to conquer their own selves.

Four days before her event at the Games, Veloso was a vomiting, diarrhoea-ridden mess after food poisoning. Still she won. Four years before the Games, life was even harder. In 2014, in Munich, she won a World Cup gold at 14, the youngest woman in shooting history to do so, and it is intriguing that a moment of such brilliance can also be a burden. Being a prodigy always is.

People think you're the chosen one and pressure covers you like a blanket. If you win at 14, why aren't you winning at 15, 16, 17? "I didn't know how to cope," Veloso says and how could she.

There is no manual on expectation, no primer on how to shrug off precocious victory and start again. So you learn to lose and suffer and survive and keep trying. Now she says that finals "make my heart race but I like that pressure. It's challenging and I like challenges".

There is no approved definition for mental toughness, but the legendary American gridiron coach Vince Lombardi once said that its qualities included "sacrifice and self-denial. Also, most importantly, it is combined with a perfectly disciplined will that refuses to give in".

Veloso is building that toughness, piece by piece, pellet by pellet. So far, she has a 2017 SEA Games gold medal in the 10m air rifle and the two Commonwealth Games golds and in August comes the Asian Games, where the shooting standard she knows is much sharper.

My last image of her at the Yishun range last Thursday is of a 5.2kg rifle snug in her shoulder, gently squeezing a trigger and sending a 8.2g pellet into the bullseye as she poses for photographers.

10.2.

Almost perfect.

So again, load, aim, breathe, fire.

The swimmer Michael Phelps once said: "If you want to be the best, you have to do things other people aren't willing to do." So you shoot for days, weeks, years. You do it till you cry and then you do it some more. You do it because of that Olympic medal which you may never get, but you have to try. This is who Veloso is, an athlete taking her best shot at greatness.