"And, uh, I told Luke, I said," and here Armstrong paused for a long time to collect himself, "I said, 'Don't defend me anymore. Don't.'
"He said OK. He just said, 'Look, I love you. You're my dad. This won't change that."
Winfrey also drew Armstrong out on his ex-wife, Kristin, whom he claimed knew just enough about both the doping and lying to ask him to stop. He credited her with making him promise that his comeback in 2009 would be drug-free.
"She said to me, 'You can do it under one condition: That you never cross that line again,'" Armstrong recalled.
"The line of drugs?" Winfrey asked.
"Yes. And I said, 'You've got a deal,'" he replied. "And I never would have betrayed that with her."
A U.S. Anti-Doping Agency report that exposed Armstrong as the leader of an elaborate doping scheme on his U.S. Postal Service cycling team included witness statements from at least three former teammates who said Kristin Armstrong participated in or at least knew about doping on the teams and knew team code names for EPO kept in her refrigerator. Postal rider Jonathan Vaughters testified that she handed riders cortisone pills wrapped in foil.
Armstrong said in the first part of the interview that he had stayed clean in the comeback, a claim that runs counter to the USADA report.
And that wasn't the only portion of the interview likely to rile anti-doping officials.
Winfrey asked Armstrong about a "60 Minutes Sports" interview in which USADA chief executive Travis Tygart said a representative of the cyclist had offered a donation that the agency turned down.
"Were you trying to pay off USADA?" she asked.