Lance Armstrong and Oprah Winfrey Lance Armstrong and Oprah Winfrey

After spending years denying that he used performance-enhancing substances during his cycling career, it only took Lance Armstrong a matter of minutes into his sit-down interview with Oprah Winfrey to admit otherwise.

Winfrey kicked off the highly publicized interview, part one of two, by asking the seven-time Tour de France champ a series of yes or no questions. Armstrong, 41, admitted that yes, he used banned substances including performance-enhancing substances like testosterone, and blood-doping. His confession came three months after he was stripped of his seven Tour de France titles and hours after he was also stripped of his Olympic medal.

Armstrong admitted he started using  banned substances cortisone and EPO during the mid-'90s. When asked by Winfrey why he chose to admit to his usage now, he said he didn't have a good answer. "I will start my answer by saying that this is too late. Too late for probably most people, and that's my fault. I view this situation as one big lie that I repeated a lot of times," he said. "I know the truth. The truth isn't what was out there. The truth isn't what I said, and now it's gone. This story was so perfect for so long."

Winter TV Preview: Must-see new shows

Armstrong found it "impossible" to live up to the "mythic perfect story" that was created and said he lost himself in the media coverage and the fans surrounding him. "All the fault and all the blame here falls on me," he said. "I certainly couldn't handle it. I was used to controlling everything. I controlled every outcome in my life."

Armstrong attributed his years-long use of banned substances partly to the entire cycling culture, which he said made it easy to dope because athletes were not tested outside of competition. Doping was simply "a question of scheduling" according to Armstrong. "I didn't invent the culture but I didn't try to stop the culture," he said. "The sport is now paying the price because of that so I am sorry for that. I don't think I didn't have access to anything else that nobody else did."

Because of this culture, at the time, Armstrong didn't feel that using the substances was wrong or bad. "I looked up the definition of cheat, and the definition of cheat is to gain an advantage on a rival or foe that they didn't have," he said. "I didn't view it that way. I viewed it as a level playing field."

Check out celebrities' dramatic weight loss

Another big reason behind Armstrong's decision to use these substances was his battle with testicular cancer, for which he underwent brain and testicular surgery and extensive chemotherapy from 1996 to 1997, at which point he was declared cancer-free. He said that struggle helped him justify his cocktail of EPO, blood transfusions and testosterone. His battle with cancer also gave him a "ruthless" desire to win. "It served me well on the bike, served me well during the disease, but the level that it went to, for whatever reason, is a flaw," Armstrong said. "And then that defiance, that attitude, that arrogance, you cannot deny it."

Armstrong was speaking about his adamant denial of using banned substances over the years. When looking at an old video in which he denied such actions, he called himself "an arrogant p-----" and also said cancer turned him into a bully. "I was a bully in the sense that I tried to control the narrative, and if I didn't like what somebody said," he said, "I tried to control it and I said, 'That's a lie. They're a liar.'"

During the interview, Armstrong still denied several allegations to Winfrey. He denied using any sort of performance-enhancing substances in 2009 and 2010 when he came out of retirement and placed third and 23rd, respectively, in the Tour de France.  He also denied pressuring other members of his team to use these substances when he was using. "The leader of any team leads by example. There was never a direct order," he said. "That never happened. It was a competitive time. We were all grown men. We all made our choices."

Remember when Justin Timberlake had curls? Check out the most dramatic celebrity makeovers

However, he acknowledged, "I'm not the most believable guy in the world."

Looking back at his lies, as well as his defiant fight against these accusations, Armstrong said he was paying the price now and that his behavior was inexcusable. "These are people that supported me, believed in me, believed me ... and they have every right to feel betrayed," he said. "I will spend the rest of my life trying to earn back trust and apologize to people."

The second part of Armstrong's interview on Oprah's Next Chapter airs Friday at 9/8c on OWN.

What do you think of Armstrong's admission? Will you watch the second part of his interview?