A 101-year-old Sikh believed to be the world's oldest distance runner retired on Sunday after ending his last race in Hong Kong on a high, describing it as one of the "happiest days" of his long life.

Fauja Singh, nicknamed the "Turbaned Tornado", finished the 10-kilometer run at the Hong Kong Marathon in 1 hr, 32 min, 28 sec - half a minute faster than at the same event last year.

"Today is one of my happiest days," the Indian-born British national, who only speaks Punjabi, said through his interpreter after he crossed the finish line with a broad smile and waving the Hong Kong flag.