The case also includes DNA evidence and eyewitnesses.
Robert Williams is accused of raping and torturing the Columbia University graduate student over nearly 19 hours.
Prunty said the defendant sexually assaulted the victim repeatedly. "These are the closest and most intimate interactions one human being can have with another. ... There isn't an inch of his body she doesn't see."
The victim memorized virtually every distinguishing physical characteristic of her attacker - including his scars and his gold tooth.
"His image is forever seared into her brain, despite all her wishes that it would go away, that she could forget him," said Prunty.
"The DNA evidence in this case is like the icing on the cake - you don't need it," added the prosecutor.
She said the victim's blood was found on a shirt Williams was wearing when he was arrested. And Williams' DNA was found on one of the victim's shirts.
In addition, she said, three eyewitnesses saw Williams in the building just before the attack.
Earlier, Williams' lawyer said it was meaningless when the victim pointed out the defendant - because anyone can see who's sitting at the defense table.
The prosecutor countered, "You don't get a better opportunity to observe somebody than being with them for almost 19 hours."
Defense attorney Arnold Levine also said whoever was responsible for the April 2007 attack has a mind that "doesn't work in a rational way."
Levine previously argued unsuccessfully that Williams was mentally unfit to stand trial.
Williams, who's 31, is being tried on 71 counts that include attempted murder, kidnapping, arson, rape and sodomy.
He faces life in prison if convicted.