Spotting my goosebumps, she walked up a few rows, sat next to me and quietly insisted: "Put your jacket on. You must stay warm before you race."
I didn't know who she was until my mother said: "That's good advice, Mrs Potts would know what she's talking about."
At that stage she was the most famous sporting person who'd ever spoken to me. And despite the fact she had a son at my school, Richard, who was also competing that day, I was thrilled and honoured that she'd singled me out for some freely given advice.
Sylvia Potts was as soft-spoken as it gets. The only time she lifted her voice to a screech was when she was cheering her son, or our school, St John's, from the side of the track.
Her infamy, attained in the unlikeliest fashion, was summed up by a commentator during her efforts in the 1500m final at the 1970 Edinburgh Commonwealth Games: "That must be the unluckiest story in the whole history of athletics."
Last night I watched the heart-wrenching footage on YouTube - one of the most enduring images in our sporting history.
For Potts, it was to be a race of 1498m. With about 50m to run, her black singlet edged ahead of two English runners. Her slender lead was enough for gold, but inexplicably she tripped 2m from the line. She clambered to her feet and walked over the line in ninth place, in 4min 25.20sec.
She entered the folk-lore of popular sporting culture.
Maybe it defined our perception of her but knowing her strength, it didn't define her. And neither did it end her career, or a long-standing coaching partnership with husband and Hastings athletics talisman Allan Potts.
She died of cancer in 1999.
Now she's remembered annually in the Sylvia Potts Classic, which was held on Saturday in Hastings, where a record 145-strong field descended on the track to celebrate an athlete who, according to her husband, "always ran to win".
About 20-odd years after her fall, I was competing in Wellington at a national secondary schools athletics meet. Again, her son Richard was competing. He won almost everything he entered, and did so again on this day in an event for which I forget the distance, but assume it was the 3000m.
He and another competitor were shoulder to shoulder before the boy from Hastings kicked it into another gear and crossed the tape first. It was exhilarating. Our coach said he'd never been involved with a more "courageous" athlete. It was a word I'd never associated with running. Until then it was a word I'd associated only with contact sports. But he was spot-on. It changed my perception of what athletics at that level requires.
Courage was something her son (who went on to compete in the 1990 Commonwealth Games in Auckland) so obviously inherited.
