Roger Clemens, left, leaves federal court with his wife Debbie Clemens and attorney Rusty Hardin following jury selection last July. Debbie Clemens testified Friday in her husband’s perjury trial. (Rob Carr/GETTY IMAGES)

Roger Clemens’s wife on Friday backed up her husband’s testimony that his former strength coach injected her with human growth hormone while the star pitcher was not present, contradicting the word of the coach who is the government’s key witness in the perjury case against Clemens.

Called to testify for the second day in the District’s federal court, Debbie Clemens told jurors she asked Brian McNamee to inject her with the drug in November 2000 in a “spontaneous, no-brainer kind of moment” after reading of the drug’s purported benefits in a USA Today article days before.

She said the article, combined with McNamee’s endorsement of the drug, prompted her to ask for the injection, not the desires of Roger Clemens.

“When I came into the kitchen and [McNamee] told me that he had some HGH, I thought ‘great,’ ” she said. “I said, ‘Let’s go into the bathroom’ and he gave me a shot.”

McNamee is the only witness to testify to firsthand knowledge of Clemens’s alleged use of performance-enhancing drugs. McNamee has said he injected Roger Clemens numerous times, and testified in May that Clemens was present when McNamee gave Debbie Clemens an injection.

Roger Clemens is charged with lying to Congress when he told a House panel in 2008 that he never used steroids or human growth hormone.

The prosecution’s questioning Friday drew out a detailed account of McNamee’s injection of Debbie Clemens, which she said occurred during the daytime at the couple’s Houston mansion while the pitcher wasn’t there.

“A lot of people in Hollywood were doing it. It was like a youth drug, to stay young,” Debbie Clemens testified.

Debbie Clemens said she and McNamee went into the master bathroom — one of 10 bathrooms in the house — and she lifted her shirt. McNamee then pinched the skin near her stomach, she said, and injected her for about 10 seconds.

When she told her husband about the injection, she testified, Roger Clemens became upset — mainly with McNamee.

The jury asked why McNamee was at the Clemens household when Roger Clemens was away. Debbie Clemens said she didn’t monitor McNamee’s comings and goings to and from their home.

Prosecutors questioned Debbie Clemens’s memory of the timing of the injection, recalling that Roger Clemens had said in a deposition and a congressional hearing that Debbie Clemens had been injected in 2003, not 2000. She said she remembered because defense attorney Rusty Hardin showed her the 2000 article that prompted her to request the injection; prosecutors noted another USA Today article about HGH from 2003, but Debbie Clemens insisted that she remembered reading the 2000 article.

U.S. District Court Judge Reggie Walton said closing arguments in the trial, which just completed its eighth week, could come as early as Tuesday.