After retiring from cycling in 2011, Armstrong returned to triathlons, where he began his professional career as a teenager, and he has told people he's desperate to get back.
Winfrey asked if that was why he agreed to the interview.
"If you're asking me, do I want to compete again ... the answer is hell, yes," Armstrong said. "I'm a competitor. It's what I've done my whole life. I love to train. I love to race. I love to toe the line — and I don't expect it to happen."
Yet just three questions later, a flash of the old Armstrong emerged.
"Frankly," he said, "this may not be the most popular answer, but I think I deserve it. Maybe not right now ... (but) if I could go back to that time and say, 'OK, you're trading my story for a six-month suspension?' Because that's what people got."
"What other people got?" Winfrey asked.
"What everybody got," he replied.
Eleven former Armstrong teammates, including several who previously tested positive for PEDs, testified about the USPS team's doping scheme in exchange for more lenient punishments. Armstrong said in the first part of the interview that he knew his "fate was sealed" when his most trusted lieutenant, George Hincapie, who was alongside him for all seven Tour wins between 1999-2005, was forced to give Armstrong up to anti-doping authorities,
"So I got a death penalty and they got ... six months," Armstrong resumed. "I'm not saying that that's unfair, necessarily, but I'm saying it's different."
Armstrong said the most "humbling" moment in the aftermath of the USADA report was leaving Livestrong lest his association damage the foundation's ability to raise money and continue its advocacy programs on behalf of cancer victims.
Originally called the Lance Armstrong Foundation, the cyclist created it the year after he was diagnosed with a form of testicular cancer that had spread to his brain and lungs. Doctors gave him 50-50 odds of surviving.
"I wouldn't at all say forced out, told to leave," he said of Livestrong. "I was aware of the pressure. But it hurt like hell. ...
"That was the lowest," Armstrong said. "The lowest."
Armstrong's personal fortune had sustained a big hit days earlier. One by one, his sponsors called to end their associations with him: Nike; Trek Bicycles; Giro, which manufactures cycling helmets and other accessories; Anheuser-Busch.
"That was a $75 million day," Armstrong said.
"That just went out of your life," Winfrey said.
"Gone?" Winfrey repeated.
"Gone," he replied, "and probably never coming back."
So was there a moral to his story?
"I can look at what I did," he said. "Cheating to win bike races, lying about it, bullying people. Of course, you're not supposed to do those things. That's what we teach our children."
Armstrong paused to compose himself before a final mea culpa.
"I just think it was about the ride and losing myself, getting caught up in that, and doing all those things along the way that enabled that," he said. "The ultimate crime is, uh, is the betrayal of those people that supported me and believed in me.
"They got lied to."
AP Sports Writer Jim Vertuno in Austin, Texas, and National Writer Eddie Pells in Denver contributed to this report.