Andrew Armstrong, 33, of Mossdale Road, Manchester, pleaded guilty to one count of rape at an earlier hearing.
The victim reported the rape to police in 2002 but the Crown Prosecution Service (CPS) decided no action should be taken.
A fresh investigation was launched in 2013 when the victim reported it again. Police said the woman had "suffered for years" and been ostracised by family.
The victim and a police officer handling the case were also threatened with rape via a text message on 12 May this year when Armstrong entered his guilty plea, police said.
The threat came from an unknown number and also contained a sexually-explicit photo.
A 59-year-old man has been arrested and bailed in connection with the incident.
Det Con Rachel Wood said: "This is one of the most harrowing cases I have ever dealt with during my years as a police officer."
She said the woman had "suffered for years" knowing she had been a victim of rape and was "further tormented" because she was "ostracised from her family who refused to believe her".
"Both the victim and myself were subjected to vile sexual threats so it is even more testament to the courage and bravery of this woman that she did not back down in the face of such disgusting threats and, as a result, Armstrong has been convicted of his appalling crime." the detective said.
"She has told me that the abuse she suffered at the hands of Armstrong ruined her life, to the point where she is paranoid the same thing will happen to her own children."
Armstrong was told he would remain on the sex offenders register for life.
Det Con Wood said she hoped the sentence at Manchester Crown Court would mean the victim could now "finally start to rebuild her life".
A man who raped a 14-year-old girl in 2001 has been jailed for six years.