Ashok Kumar (42) had gone to the victim's apartment at around 12:30 pm yesterday and allegedly raped her before fleeing, they said.
The accused was known to the woman and used to frequent her residence at Military Road, police said.
"Though earlier we suspected that Kumar visited the victim's place with an intention to commit robbery, but now it is clear that robbery was not the motive," said a senior police officer.
According to police, the victim called her neighbours for help after the crime and was later taken to Bombay Hospital, where she is currently undergoing treatment.
The watchmen of the building in their statements too said that they had seen the accused visiting the victim on at least two occasions.
Based on the description given by the woman, Kumar was arrested from Tata Power Line area in suburban Borivili in the morning.
