He grabbed her by the shoulders and she managed to break free and run into Vaughan Street.
But the offender caught up and pushed her to the ground before sexually assaulting her.
The teen broke free a second time and fled the scene.
The man is described as Caucasian in appearance, aged in his early 20s, 180 centimetres tall, with curly brown hair, and bushy eyebrows.
He had a deep voice and was wearing a grey hooded top.
Investigators have released an image of a man they wish to speak to.
Police have urged anyone with information to contact Crime Stoppers.