The attack occurred in northeast Lincoln just after 5 a.m. Wednesday. The woman told police she was asleep in the living room of her apartment when she awoke to a man armed with a knife.
She says he initially demanded her belongings before attacking her. She was taken to a hospital with visible bruising and swelling to her face.
Police say the only description they have of the suspect is that he was wearing dark clothing.
Investigators believe the man may have entered the apartment through an unlocked window.