Hongkonger Jeanie, 15, is officially the fastest female in the event after winning the overall title at this year's world championships in Butzbach, in Germany. She won three silver medals in her age group's mixed-gender categories, but was also crowned overall women's champion thanks to a combined time of only 9.756seconds for the tournament's three events - making her the world's fastest women's sports stacker.
The Year 10 student at West Island School took an interest in the sport after she saw a set of cups displayed in a toy shop while on a family holiday in Japan about four years ago. "I'd never seen such toys in Hong Kong before," says Jeanie.
"I couldn't read the Japanese words printed on the box, but took away a leaflet in English so I could read it."
She researched the sport - looking up the English word "stacking" online and watching short films on YouTube of competitors stacking cups as fast as they could. "It helped me get the basic idea and I really wanted to try," she says.
The sport - also called cup stacking and speed stacking - originated in the United States in 1990 and has more than 400,000 regular participants worldwide.
Competitions involve three ways of stacking special plastic cups - a 3-3-3 formation of nine cups, a 3-6-3, 12-cup formation and a cycle formation, involving a variety of combinations. Athletes must stack cups in a set order (known as "upstacking"), and then unstack (or "downstack") them within the shortest time possible.
Jeanie's father helped her start by buying her four sets of colourful stacking cups and a special mat with a time sensor, which he found on sale during a business trip in Canada. "Having four sets at the same time was quite nice as cups wear out or break when you practise frequently," says Jeanie.
She practised hard - teaching herself to play by following the instructions included on the sets and watching demonstrations of players on YouTube. She made her debut in a local competition in 2009.
Soon Jeanie was doing well in tournaments and claimed the Hong Kong record for sports stacking in 2010 while winning three individual and one doubles title. That same year, she competed in the World Sport Stacking Association's World Championships, in Denver, in the US - finishing in the top 10 in the 3-6-3 category. At last year's event, in Dallas, she finished in the top 10 in both the 3-3-3 and 3-6-3 events.
Many of her contemporaries may switch their attention to new toys or interests as they grow older, but Jeanie's focus on sports stacking has remained firm over the years. "I like stacking because I can always challenge myself to complete the stacks faster than before," she says. "The feeling of breaking records is great.
"I'm less nervous when I compete now, compared to when I started. Being nervous can cause your hands to sweat, and sticky hands can really slow down the stacking process.
"I'm also better at adapting to changes in environment and humidity; even the lighting, which all can affect our touch on the cups.
"I had better physical and mental control at this year's world championships in Germany, too."
Her success inspired her mother, Bobo Fung, to partner her in last year's parent and child doubles event at the Asian Championships in Singapore. But her mother found the sport was daunting.
"When Jeanie was competing, I felt nervous because I couldn't help her," Fung says. "I would shout out to her the time of her strongest rival before she competed. Yet when it came to my turn, the pressure was more intense than I'd ever imagined."
Winning the world title has inspired Jeanie to focus on more glory. "From time to time I watch videotapes of myself in action to spot glitches in my technique in each move I make," she says. "I also try to learn from watching other stackers' moves. I hope I can keep winning medals."
Jeanie has also set up her own YouTube video channel, Jeaniustacks, so you can see just how fast she is at sports stacking.