Man Arrested Over Sexual Assault Of Woman In Melbourne Park

A man has been arrested over the alleged sexual assault of a woman in a Melbourne park over the weekend, during which the victim escaped by stabbing the offender with his own knife.

The 21-year-old man, who has no fixed address, handed himself in to Preston Police Station at about 11am on Monday.

He remains in custody where he is being questioned over the sexual assault of a woman in Thornbury's Mayer Park on Saturday night.

The 32-year-old woman was walking her dog in Thornbury at about 10.30pm when she noticed a man ahead of her acting suspiciously, police said.

She walked into Mayer Park to avoid the man, but he approached her and asked for help finding something he had lost.

"He then produced a knife, he threatened her, pushed her to the ground and sexually assaulted her," Detective Acting Inspector Janet Michell said.

Mayer Park. Image: Google Maps

During the attack, the woman managed to grab the offender's knife and stabbed him.

The attacker left blood at the scene and would likely have sustained a serious puncture wound, police said.

"I think it's quite frightening," Michell said.

"I think he was on a mission and he saw the woman coming and he pursued her."