Paul Lim and Harith Lim might have to squint to read now, but they need no aids to hit a bullseye on a dart board from 2.5m away.

And while the sport has evolved from using steel-tipped darts to soft-tipped ones, their mental composure has gone the opposite way.

Hands and fingers no longer tremble when Paul, 63, and Harith, 47 - who have over 60 years of competitive experience between them - step up to the throw line.

Harith said with a tinge of incredulity in his voice: "How to beat Scotland when you feel nervous? We were not nervous at all. We are not new kids on the block anymore."

He was referring to their sensational upset last month at the World Cup of Darts, where the Singaporean duo shocked top seeds Scotland en route to a quarter-final finish at Frankfurt.

Their achievement made headlines around the world, with Sky Sports in Britain and the Bleacher Report in the United States carrying news of the upset.

In Singapore, the news went viral, with Singaporeans taking to social media to praise the duo and thank them for flying the Republic's flag high on the world stage.

For that, the pair won The Straits Times' Star of the Month award for June. They are the first darts players to win the accolade, an extension of the ST Athlete of the Year award, since it was introduced in 2008. Both are backed by F&N's 100Plus.

Paul is also the oldest athlete to ever win the award. But being on the receiving end of such adulation and awards is not foreign to them.

In 1990, Paul, then 36, made waves by being the first man to record a perfect nine-dart game at the World Championship.

Harith was a former world youth champion in 1986, who also picked up two junior meritorious awards at the Singapore Sports Awards in 1987 and 1988.

But while they have a lifetime's experience to carry them through a competition, things are not getting easier.

Standing for 10 to 12 hours during competition days requires extra conditioning compared to when they were younger.

Paul said: "You feel the difference. You feel more tired and your legs get weaker...

"People don't realise that it takes a lot of stamina and determination."

He even watches his diet these days, shunning his favourite roasted goose and duck meat in favour of healthier choices, no mean feat given that he is based in Hong Kong.

"All these sacrifices I have made contribute to what I am still doing now. It's because I want to do well," he added.

ST Sports Editor Lee Yulin said: "I have long believed that any sporting achievement - regardless of whether it is in a popular sport, or a less mainstream sport such as darts - is worth celebrating.

"Paul and Harith put Singapore on the world map with their World Cup performance. ST and 100Plus are pleased to honour them for their achievement."