Two teenagers looking for a cheap thrill got a beatdown when a jogger who they assaulted turned out to be an expert in martial arts.

According to Kval.com, Priscilla Dang was jogging in her Vancouver, Wash., neighbourhood last Friday when she was approached by two teens on their bikes.

One pulled in front of her as the other groped her from behind.

Little did they know that Dang had studied kung fu for 18 years at a martial arts school owned by her family.

"I grabbed him and said, 'You need to apologize, and he did,'" Dang is quoted as saying on Kval.com.

Then the second teen started swearing at her.

Dang said that something snapped inside her and she punched him twice in the face.

"He started coming in for a few, and I was lucky enough to dodge his shots. I came up for another one and I got him good, and I think that upset him," she told the news station.

Things escalated when one of the punks pulled out a knife, said Dang, and her instincts kicked in telling her to back off and play it safe.

Two people witnessed the confrontation and called 911. Police say an 18-year-old was arrested while the younger suspect was turned over to his parents.

"I think they knew they messed with the wrong girl," Dang said.