As she lays her sore, aching body down to rest each night, Shanti Pereira spends a moment reminiscing about the 200m race at last month's SEA Games.

The next morning, as she slips on her spikes for another gruelling training session, she watches the race again.

She relives that brief 23.60sec not to bask in her moment of glory, but because she needs that comforting reminder - that for every low and seemingly hopeless lull in an athlete's career, there are also dizzying highs such as these.

Before the nation witnessed her record-breaking feats at the Games, including the 200m win that ended a 42-year drought for the Republic in that event, Singapore's sprint queen spent months in the deepest, darkest valley of her fledgling career.

The 18-year-old, after competing in both the Commonwealth and Asian Games last year, suddenly found herself plateauing, unable to shave any time off her personal bests for the next five months.

"I wasn't doing good timings at all at every meet that I went to," said Pereira, whose achievements at the SEA Games earned her The Straits Times' Star of the Month award for June.

She finished in 23.99sec for a new national record in her pet event at the Asian Junior Athletics Championships in June last year. One month later, she clocked 23.87 at the World Junior meet but this was not recognised as a new national mark because of the wind speed.

After that, however, came the drought, when she struggled to clock another sub-24sec.

In the 100m, she was routinely finishing in 12.30, far off her then-PB of 11.89. It led to months of frustration and self-doubt.

She recalled: "I was asking myself, 'Is this it? Is this all I can do'?"

She said she got through the period with the support of her family - especially older sister Valerie, also a former national sprinter - and coach Margaret Oh.

But the lean spell taught her a valuable lesson in persevering through the ups and downs of a sporting career.

She said: "I have to be patient because this is part of an athlete's life. There are going to be so many downs before you reach that up."

The breakthrough finally came in March at the Singapore Open. She clocked 11.80 for a new national record in the 100m, and hit 24.00 in the 200m.

"My desire to do a personal best was so strong that I couldn't do it. I've learnt my lessons. I'm a better runner if I'm just completely clear in my head," said Pereira.

But that is not to say the Singapore Sports School alumna has not set her sights higher.

Due to compete in the World Championships at Beijing's iconic Bird's Nest Stadium next month, she said: "I'm hoping to see myself go even further, reach different platforms and do well there."

"I have more belief in myself (now)," added Pereira, who is 0.4sec away from the Olympic qualifying time.

"I want to qualify for the Olympics, and to do that, I need more time to cut down my timing.

"I see next year's Rio Olympics as something I want to go for, but the main goal is 2020 ."

Each time she replays her 200m SEA Games win in her head, Pereira can feel the euphoric sensation as she strode across the finish line that evening, the "vibration" of the National Stadium, with more than 10,000 spectators on their feet, cheering her on.

She said: "Every time I think about it, I still feel like my heart is going to burst out of my chest.

"The fact that it happened is pretty amazing for me, and it's something I will never forget."