When she went to help, he produced the knife. The woman then managed to grab the knife and believed that she stabbed him, before running to safety.
Blood at the scene led police to believe her attacker was injured before he fled.
“I think he was on a mission and he saw the woman coming and he pursued her,” acting Inspector Mitchell said.
“When he could see that she was trying to get away, he tried to divert her attention appealing to her good nature.”
The woman ran onto the road and flagged down a passing motorist to get help. Her attacker was last seen running down Leinster Grove.
Detective acting Inspector Mitchell said the attack happened very quickly.
There was a party in a hall nearby. There were also houses close to the scene of the attack.
Residents were left shocked by the attack in what was normally a “really friendly, happy place”.
One man told Channel Nine people often used the gym equipment in the park at night, and there were normally families walking their dogs and kicking footballs until quite late.
“It’s just shocking,” he said. “You don’t expect that kind of stuff in this neighbourhood.”
The woman spent the night in hospital before being released on Sunday morning.
Public Transport Minister Melissa Horne told reporters on Sunday every woman deserved to be safe regardless of the location.
“Whether it’s in the park, in their home, walking down the street – wherever they are, every woman deserves to be safe,” she said.
Ms Horne said the government was upgrading CCTV across train stations and more protective services officers were patrolling public transport.
“These are things directly within my portfolio area that I’m going to make sure that women are safe.”
The assault has echoes of a series of attacks on women in public spaces in Melbourne in the past few years, many in the northern suburbs.
Comedian Eurydice Dixon, 22, was raped and murdered in Princes Park in June 2018.
In January, international student Aiia Maasarwe, 21, was attacked and killed as she walked home in Bundoora, and Courtney Herron, 25, was bashed to death in Royal Park in May.
If you or anyone you know needs support, you can contact the National Sexual Assault, Domestic and Family Violence Counselling Service on 1800RESPECT (1800 737 732).
With Robyn Grace
Sumeyya is a reporter for The Age.