Cassadee Pope Cassadee Pope

She was No. 1 on the U.S. iTunes chart the same night that she was crowned the Season 3 winner of The Voice, but Cassadee Pope says that she didn't expect to win the competition. She actually thought that she was going to get the boot weeks ago.

"I kind of thought at the knockouts that I was done. I was not happy with that performance," the 23-year-old told reporters backstage after winning the singing competition. "That was probably my lowest moment as far as my performance, but I think seeing iTunes has helped me get through this season with a little bit more ease. It gave me a little bit of a heads-up for what was going to happen."

The Voice: Who won Season 3?

Her coach, Blake Shelton, never shared her criticism, but admitted that he had doubts that she would be able to hold on to the front-runner status she gained with her memorable performance of "Not Over You" more than a month ago. "The hardest thing to hold on to is if you peak too early in this competition and that's what so special about Cassadee," he said. "To be able to hold on to that type of momentum is impossible and you have to be somebody special."

Shelton might have been her mentor throughout the competition, but he said Pope was always her toughest critic. "I don't know anybody who's ever beat themselves up more than Cassadee does week after week. Last week, she did 'Stupid Boy' and she was like, 'Oh my God, it sucked so bad. It's over. It's over.' And I held up my phone and she was already No. 1 on iTunes," Shelton recalled. "She's an artist. She's never going to be totally happy with what she does, but I hope she's really happy that she won this."

Pope was beaming backstage after her win, but she was hardly alone. Her win marked Shelton's second triumph as a coach, following Jermaine Paul's victory last season. Additionally, Shelton's other finalist, Terry McDermott, finished second for the season. "He's a great guy. He does the little things that the media doesn't know about," host Carson Daly said of Shelton. He hired Season 2 singer Gwen Sebastian to sing back-up for him, and Season 2 finalist RaeLynn is "practically living" at the house that Shelton shares with wife Miranda Lambert, according to Daly. "I think America knows that. If you go with Blake, you may not win, but you may get some help."

Watch videos from The Voice