Nine-year-old Isabelle Ward left runners twice her size in her wake as she was first across the Race for Life finishing line.
Isabelle, who attends Dene House Primary School, in Peterlee, completed the 5k course in just 23 minutes.
The youngster led the way at the front of a wave of pink that swept through Seaton Carew as more than 700 women raised tens of thousands of pounds for the fight against cancer.
Sunday’s Race for Life proved another big success and an emotional day as runners, who had all been touched by the disease, joined together to raise money for research.
They ranged from all ages, including babies in pushchairs, and came from all over the region to take part.
Afterwards, the exhausted youngster said she was pleased to win, but felt tired.
She said: “I only do running at school.” Isabelle was cheered over the line by her uncle Brian Ward.
He said: “I think it’s unbelievable she has won. I nearly had tears in my eyes when she was coming across the line.
“She is a good runner and has done it in the past for school, but to see her coming first at the age she is really surprising. I’m over the moon.
“She is doing it for all her great-grandparents who have passed away from cancer, so it is in memory of all those people.”