The man grabbed the woman but she called out and swung her dog lead at him which made him run off.
The Police Service of Northern Ireland (PSNI) are investigating the possibility that this attack is linked to an attack in Drumahoe on Friday.
Police searched the area following the attack on Saturday, but the man had left the area.
It’s believed the suspect headed in the direction of Corrody Road.
He is described as a white man in his 20s, around 5ft 11in (1.83m) tall with a slim build and wearing all black clothing.
The attacker reportedly had his hoody pulled tight around his face.
In a statement Dt Insp Ross Olphert said: “We understand that there will be concern in the community at a second knifepoint attack on a woman in just two days, with this latest one occurring during daylight hours, however I can assure residents that a focused, tactical patrolling plan – which includes a high visibility police presence in key areas such as our local parks – has been implemented and there will be an increased police presence across the city in coming days.”
The PSNI have said that enquires are continuing to establish if there is a link between the two attacks in County Londonderry.
The police said there is no link between the two weekend attacks and earlier attacks in the city centre last week.
Police have called for anyone with information to come forward.
