He said he was given seven prescriptions for the now-banned sedative, ostensibly for a sore back. They said she had called him more than 70 times in the weeks after the encounter. She said she believed they were some kind of an herbal remedy to help with stress, so she took them because she trusted him, and soon became incapacitated.
In this case, Cosby's defense attorney Tom Mesereau has argued that Constand was a "con artist" who was obsessed with Cosby's money and fame.
Prosecutors are building to the conclusion of their case against Cosby with investigators and a pharmaceutical expert expected to take the stand beginning Tuesday in the comedian's sexual assault retrial.
For example, she told police that on the night of the assault in January 2004 she called Cosby to open the gate.
Prosecutors on Monday delivered a one-two punch as chief accuser Andrea Constand rejected defense allegations that she concocted her story to score a big payday, and her mother testified that Cosby apologized.
Mesereau clawed back, making clear to jurors that Constand's answers have varied on the date of the alleged assault, how often she dined out with Cosby, whether she made a point of wearing a cashmere sweater he gifted her to one of their meetings and where she wound up when she visited his room at a CT casino.
Constand said prior to the alleged assault, she had considered Cosby a mentor from whom she sought career advice. At moment, she had been director of operations for its ladies's basketball team at the entertainer, Temple University's alma mater.
Gianna Constand, left, and her daughter Andrea Constand, right, walk toward the courtroom inside the Montgomery County Courthouse.
His successors reopened the criminal case in 2015 after Cosby's testimony from Constand's civil suit was unsealed.
Later, prosecutor Kristen Gibbons Feden read Constand the definition of a pyramid scheme and asked Constand whether that accurately described the business she was involved in. "This isn't about money".
Constand's mother followed her on the witness stand and bolstered her account, testifying about a phone conversation she said she had with the comedian about a year after the alleged assault in which he described in graphic detail their sexual account and then apologized.
The comments came on the second day of testimony for Constand, the former Temple University employee who testified that Cosby acted as a mentor to her, gained her trust, and then drugged and sexually assaulted her in 2004.
She said when she went to his home in suburban Philadelphia in early 2004, he offered her three blue pills to help her relax.
"He said to me, 'Don't worry, Mom, there was no penile penetration, ' " Gianna Constand shared with the court.
Bliss then attempted to show that Gianna Constand did not know everything going on in her daughter's life, and therefore wouldn't know if she was "having an affair" with Cosby.
She told jurors last week that Cosby knocked her out with pills and then sexually assaulted her. Cosby, 80, says Constand consented to a sexual encounter. His first trial ended with a hung jury.
The victim's mother's testimony was pivotal in last year's criminal trial of Cosby.
On Monday, the defense tried to cast Constand as an opportunist who baited Cosby by feigning romantic interest in him.
Gianna Constand testified that Cosby said during the phone call that he was a "sick man".
Cosby has denied that the accusations.
Ms Constand told the court that she does not know Marguerite Jackson - a woman who the defence plan to call as a witness as part of their attempt to discredit her. At the time, Judge Steven O'Neill ruled Jackson's testimony would be hearsay.