Kelly Herron, 36 from Seattle, was four miles into a ten mile run through a busy park last Sunday when she stopped to use a public bathroom.

As she was drying her hands she “became aware that something was wrong” and turned around to see a man, who had been hiding in one of the toilet stalls, standing behind her.

“He immediately took me down to the ground, hit both my knees and legs, and then it was a fight on the bathroom floor and I just kept screaming, 'not today m***** f*****,’” she told ABC News.

As she was beginning to lose consciousness, she decided that “this doesn’t have to be a fair fight” and began fighting back.

“All those little things that I learned in my life… how to punch and everything came back to me,” she said. “I learned [to aim for] hard bones and soft fleshy places so I just started hitting the side of his head."

Sharing a photo of her bruised and bloodied face on Instagram (below) she wrote, “I fought for my life… clawing his face, punching back, and desperately trying to escape his grip - never giving up.”

Jogger fights off sex offender who attacked her in a bathroom