Sussex Police said: “The victim was pushed up against a wall by a man who then pulled his trousers down and exposed himself.
“The woman pushed the man and ran away unharmed.”
The incident took place on Bolsover Road at around 7.30pm.
Officers received another report of a woman being followed by a man along Wish Road around 9.45pm on the same day. The man asked to walk alongside the woman but she refused and walked off, police said.
Investigating officer Matthew Stevens said: “We believe the two incidents reported to us could be linked. We are urging anyone with information on either of these incidents to get in contact with us without delay. Did you notice a man acting suspiciously in this area?
“To report information please go online or call 101 quoting reference 1112 of 23/01.”
Sussex Police said a 33-year-old man from Hove was arrested on Friday (January 25) on suspicion of sexual assault on a female. He remains in custody at this time and the investigation is ongoing.