Constand - then an athletic, 6-foot-tall college basketball staffer - said they made her dazed and groggy, and unable to say no or fight back when Cosby went inside her trousers.
"Drugging somebody and putting them in a position where you can do what you want with them is not romantic".
"Ladies and gentlemen, he has told you what he has done", Montgomery County District Attorney Kevin Steele said in his closing argument.
Cosby's lawyers repeatedly challenged Constand's recollection of events, and called into question her credibility, noting she only reported the incident to police about a year after the alleged attack, and then changed her story three times during interviews.
On Monday, the actor's high-powered defence team called just one witness to the stand - Richard Schaeffer, a detective who helped take down Constand's original statement - and rested their case in just a handful of minutes.
The defense closed by accusing Constand of lying about an affair with Cosby and concocting the allegations to take advantage of the wealthy, older star.
Legal experts said testifying would have been a risky move that could have opened the TV star to withering cross-examination about some of the 50 or so other women who have accused him of drugging or molesting them. They complained that prosecutors were improperly striking blacks from the jury chosen in Pittsburgh.
Jurors soon will hear closing arguments.
Constand, under the influence of the drugs and who briefly lost consciousness, could not and did not give consent, he said. Andrea stayed silent, and so he began "telling me everything that he physically did to her", Gianna said. Cosby, as expected, waived his right to testify.
During closing, McMonagle repeated to the jurors that Cosby's life is in their hands.
McMonagle pointed out that Constand telephoned Cosby dozens of times after the alleged assault. He said that the comic's 2004 sexual encounter with Ms Constand was consensual and that they had been intimate before.
Cosby said that he couldn't read the letters on the prescription bottle, and asked her to put Andrea on the line.
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Mr Cosby arrived at court on Monday with his wife, Camille, who made her first appearance at the high-profile trial in Norristown, a suburb of Philadelphia.
"When you dance outside of marriage you gotta pay the band", McMonagle said. She testified that nothing romantic happened in the hotel room, and that she made those phone calls as part of her job at Temple.
Prosecutors also called a second accuser, Kelly Johnson, who told jurors that Cosby sexually assaulted her in a similar manner in 1996.
"This isn't talking to a trustee".
If found guilty, Cosby could go to prison for the rest of his life.
Later, he told Crime Online that a jury will have to decide Cosby's guilt based on one factor one factor alone. Still, if it comes to be, Cosby will have faced his criminal comeuppance in the single case that has come to trial. Cosby, his lawyer said, never ran from talking to police, for better or worse.
Constand didn't react to McMonagle's closing but smiled at the end of it.
Prosecutors will give their closing argument Monday afternoon.
Her lawsuit against him had elicited four days of testimony from Cosby about his sexual conduct with some of them. O'Neill asked Cosby if he discussed the issue with his attorneys and if he understood there is no obligation to testify, as the burden to prove the charges of aggravated indecent sexual assault case lies exclusively with the prosecutors.
Defense attorney Brian McMonagle's arguably biggest courtroom drama, the sex assault trial of entertainer Bill Cosby, has been a legal rematch with prosecutor Kevin Steele, who was on the opposing - and losing - side of a almost identical 2014 rape case.
"Ladies and gentlemen, he has told you what he has done", Steele said. Legal experts and courtroom observers generally dismissed that suggestion as a bluff, perhaps created to throw the prosecutors off-balance at a time when they had momentum.