Every winning stroke off Ratchanok Intanon's racquet draws a squeal of delight from the dozen or so children taking a break from practice, and a celebratory drum roll on a trestle table from the 17-year-old player's parents.
"I never imagined she would go to this competition," said her mother Kampan, who has worked at the Banthongyord Badminton School for more than two decades, sporting flip-flops and a polo shirt emblazoned with her daughter's name.
"I am so proud of her. But whatever happens she will come back here to be with her family. She is still so young."
Thailand boasts few top class athletes and Ratchanok, ranked ninth in the world, represents one of its few genuine chances of a medal in London.
She has caught her country's imagination as much for her modest upbringing -- her parents are migrants to Bangkok from the country's hardscrabble northeast, with her father a driver at the school -- as her on-court exploits.
On Sunday she breezed by her first rival Thilini Jayasinghe 21-13, 21-5, much to the approval of her seven-year-old brother Ratchaporn. "I am so happy," he said, beaming a toothless smile. "I hope she brings me a medal."
If she does, the three-time junior world champion will owe a lot to the Banthongyord school, where she has lived since she was a baby and now sleeps in a bunk in a cramped dormitory with several other girls.
It usually charges athletes 8,500 baht ($270) a month for coaching, food and accommodation but Ratchanok has received free full-time lessons since she was young to keep her occupied while her parents worked.
She first took to the courts aged six, and more than a decade later a collection of trophies dominates the cabinets, while newspaper cuttings of her achievements proudly adorn a wall in the reception, which doubles as a canteen.
By all accounts shy and humble -- highly prized traits in Thai culture -- Ratchanok has swept domestic and international honours at junior level. But coaches, friends and family at Banthongyord are convinced she has what it takes to step up.
"Her chances of a medal are 50-50 -- there's a strong German and a Chinese girl in her side of the draw," says the school's principal Kamala Tongkorn.
"If she beats them, she can take gold," she told AFP.
"But it doesn't matter either way. We're already so proud of her... she knows how to practice and look after herself. There's nothing I can tell her any more."
Stretching out on a mat after training, Ratchanok's 16-year-old friend Karnjanavadee Bunsomboon says she has been sending her constant text messages of support, adding with a laugh that a podium place will bring fame to Banthongyord.
"Lots of foreigners will come -- they can play badminton and we can practise our English."