It happened just after 2 p.m. Thursday at Maya's Mini Market on Adams Boulevard.
According to store owner Rena Amaya, the suspect was shopping when another customer came in and made a large wire transfer. When the customer left, the suspect also walked out but came back shortly after.
The owner said the suspect asked the clerk about a product from behind the register but suddenly attacked her.
The video, which was captured by a store surveillance camera, shows the suspect pointing a knife at her.
After a brief struggle, the clerk managed to grab the knife from him and run him out of the store.
"When the lady grabbed the order ... the guy came around the counter and he pointed at her a big knife," said owner Amaya. "But the [clerk] is a brave girl, but she fought against him. She got the knife and she chased him ... trying to get him."
The clerk said Amaya usually monitors the store's activity on his phone. She tried to call him, hoping he'd hear or see the commotion, but he didn't.
The suspect remains on the run.
Amaya has since filed a police report.
Anyone with information is urged to contact police.