Newspaper Correio da Manhã (CM) reports the attack took place in the woman’s Almancil home during the early hours of 1 January after the man had been out celebrating the New Year.
According to the newspaper, the suspect returned home and knocked on the woman’s door on the pretence his water pump was broken, before attacking her and consummating the rape.
After the attack the British victim managed to escape onto the street to find help.
A car passing through the area stopped to help the victim and called the GNR, who immediately went to the property.
CM claims the attacker was in Portugal on a temporary residency visa, and was still at the scene when GNR officers arrived, subsequently being arrested and taken to the Almancil GNR police station.
As it involves rape, the case was handed over to the PJ police to investigate.
The suspect is being held in police custody pending trial.