In awe at those beautiful and powerful creatures he had never laid eyes on before, Tan was also intrigued by those little men sitting perched atop.
Sporty (he loves his football) and being a bit of a speed junkie, the then 21-year-old could picture himself doing that, more so when he was slight of build. He applied for a position as an apprentice jockey under the Singapore Training Academy for Racing (STAR) programme, and to his delight, he was accepted.
Seven years later, that venture into a hitherto unknown world has paid dividends with a first winner at Kranji – $108 outsider Rapid Fire in Sunday's opener, the $30,000 race over 1000m on Polytrack.
After spending five years with Singapore champion trainer Mark Walker, Tan joined Jason Lim last year, but the thankful apprentice is not one to forget his roots.
"Mark Walker was the first trainer I joined when I signed up for the STAR programme in 2014. I have to thank him for his guidance all these years," said Tan.
"He even sent me to New Zealand in 2017 and 2018. I didn't ride in races, only in trials, but it was a very good experience.
"Of course, I have to also thank Jason Lim for the opportunities since I joined him, (Singapore Turf Club riding coach) Matt Pumpa, (Lim's assistant trainer) Richard Lim, CC (Chin Chuen) Wong for picking up my mistakes and giving me a lot of advice.
"One person I'd like to also thank is ex-jockey Taib Affandi, who now works for Jason; he guides me a lot. My boss has also spent a lot of time with me, building up my riding skills and he's given me a lot of rides."
The Lim-trained Rapid Fire was Tan's ninth ride – with all previous eight hailing from the same source – since he began his budding riding career on January 1.
Lim did let in Tan had to cop a few sprays after some of his rides, but it would seem the listening pupil is a fast learner.
After dropping Rapid Fire at the rear on the fence, Tan was seen getting on his bike at the halfway mark, electing for the periphery to launch the US-bred four-year-old by Cross Traffic for his run.
Showing great poise and vigour in the saddle, Tan drove Rapid Fire hard inside the last 200m, finishing right over the top of their rivals to score by half-a-length from Hero Star (Tengku Rehaizat) with Trigamy (Yusoff Fadzli) third another length away. The winning time was 1min 0.16sec for the 1000m on the Polytrack.
"It felt awesome and great to get that first win," said Tan.
"Once the horse had a free run on the outside, he did his best work and ran to the line very well.
"I'd like to dedicate that win to my wife Yuki, who has been my biggest supporter from Day 1 and my four-and-a-half month old son Ethan as well."
Lim was also rapt the "raw diamond" has not taken long to shine in his new chosen career.
"It's nice to see my apprentice ride his first winner," said Lim, himself a relative newbie having only started training last year. "I have to support him with rides, just to get him going, and he rode this horse very well today.
"Last week (January 1), he ran with blinkers on and got a bit keen. I dropped the blinkers, told Dennis to put him behind as the pace would be fast, and just let him run home."
With that second win in 11 starts, Rapid Fire has now brought up in excess of $30,000 in stakes for the Hotspot Racing Stable.