The attack happened at the intersection of W. 75th Street and Broadway around 2:30 a.m.
Investigators said the woman, 20, was approached from behind, thrown to the ground, assaulted and then sexually assaulted by the suspect as he put his hands inside her underwear.
The victim fought the attacker off and the suspect fled on foot.
The victim was treated at an area hospital for minor injuries and released.
The suspect is described as a Hispanic man, 30-40 years old, 5'7", 200 lbs. He was wearing a black polo shirt, and black pants at the time of the attack.
Anyone with information is asked to call Crime Stoppers at (800) 577-TIPS (8477). You can also submit tips by logging onto Crime Stoppers' website at www.nypdcrimestoppers.com or by texting tips to CRIMES (274637), then enter TIP577.
All calls are strictly confidential.