Paolo Kretteis, 22, from Northolt, in west London, attacked a woman during a night out in October 2019.
He lured the victim to a secluded footbridge before grabbing her around the throat and punching her in the face.
He was caught on CCTV fleeing the scene wearing his “Princeton” rugby top and sporting a distinctive man bun.
He struck again just a couple of months later when he violently attacked and raped a second woman at her west London home.
Quizzed by police, Kretteis denied ever having a man bun but his lies were unraveled thanks to his own Instagram feed.
Isleworth crown court heard Kretteis, a high-flying student accepted to Princeton on a scholarship, had been expelled from the Ivy League university in May 2019, less than a year into his studies, for a sex attack on a classmate.
Sentencing him on Friday to 18 years in prison, Judge Giles Curtis-Raleigh said the first attack was “chilling” and showed Kretteis took “real pleasure in her fear, pain, and humiliation”.
“She was terrified she was going to die,” the judge said.
He said the disciplinary finding and Kretteis’s expulsion from Princeton did not amount to a previous conviction, but was the “clearest possible, stark, and plain warning that his behaviour was wholly unacceptable and wrong”.
Judge Curtis-Raleigh said: “It’s a measure of your arrogance, entitlement, and lack of respect for women that you, instead of being deterred by what happened in America, went on to commit (these) serious offences.”
The trial heard how Kretteis had been out drinking with teammates from the Ealing Trailfinders rugby club when he came across a woman in her mid-20s outside The Chatsworth, in Acton, in the early hours of October 13, 2019.
He offered to walk her home before luring his victim to the secluded footbridge, striking her in the face repeatedly before raping her.
During the attack Kretteis asked the woman to smile to see if she still had all her teeth, then immediately punched her in the face again.
The traumatised woman eventually managed to escape when Kretteis was distracted by a passerby and found refuge with a passing taxi driver.
The court heard how the woman has been left with “consistent feelings of anger and uncontrollable crying” and has flashbacks to the attack.
She also struggles to work when “overcome by a sense of sadness”.
A picture of Kretteis was circulated by police after the attack but he went on to rape another woman on December 15, 2019.
The victim, in her 20s, was left with bruising and bite marks on her face and throat as well and had clumps of her hair pulled out.
The court heard how Kretteis had “tried to strangle” the woman and attempted to convince her to retract her allegation suggesting she “was being dramatic for reporting it to the police”.
The woman said had started sleeping with a kitchen knife next to her following the attack and was suicidal.
Kretteis, an A* student who was selected for Brazil’s under 21 rugby squad, denied he was the person on the CCTV following the first attack, insisting he had never worn his hair in a distinctive man-bun.
But his claims were undermined by his own Instagram feed, while the Princeton sports top was recovered from his home.
The court heard on Friday how the former mechanical and aerospace engineering student continues to deny the incident that led to his expulsion from university, insisting that he and the alleged victim had consensual sex.
Kretteis started studying for a degree since being taken into custody more than a year ago.
The rugby player denied but was convicted of two counts of rape and making a threat to kill.
He pleaded guilty to two counts of causing actual bodily harm on the first day of his trial.
He will serve at least two-thirds of his prison sentence, and will have five extra years on licence after his release.
Kretteis will be on the sex offenders register for life.