An 18-year-old woman was raped and stabbed by an unknown attacker in a Wynnefield Heights motel late Wednesday, and a pedestrian fought off her would-be rapist in Point Breeze early yesterday.

The assaults were unrelated.

Police quickly nabbed a suspect in the Point Breeze attack but continued seeking suspects in the motel case.

The violence started about 9:30 p.m. Wednesday when police found the 18-year-old - battered and bleeding and with her hands bound by a shirt - at the North American Motor Inn on City Avenue near Belmont, police said.

The woman told police that her attacker had raped her and slashed her neck with a knife. She remained in critical condition yesterday at Thomas Jefferson University Hospital.

Special-victims-unit detectives declined to comment further on the case yesterday.

Less than seven hours after the motel attack, a 45-year-old woman walking on 21st Street near Dickinson about 4 a.m. was grabbed from behind by a man she didn't know, police said.

The man punched her in the face, forced her to the ground and pulled a condom from his pocket before the woman was able to kick him and flee on foot, police said. The attacker chased her down and tried to subdue her by pulling her hair, police said.

Instead, the woman began screaming and fighting more ferociously, prompting her attacker to flee on foot.

The woman called 9-1-1 and described her attacker to police, who quickly stopped a suspect fitting her description a block away at 21st and Tasker streets, police said. The victim identified the man as her attacker and police arrested him.

Kenyell Worrell, 27, of Fitzwater Street near 22nd, was charged with attempted rape, recklessly endangering another person, simple assault and indecent assault, police said. *