Less than one minute into his concession speech in New Hampshire, Marco Rubio 'fessed up.

"I know many people are disappointed. I'm disappointed with tonight. I want you to understand something. Our disappointment tonight is not on you. It's on me. It's on me," he told supporters at his watch party at the Radisson ballroom in downtown Manchester. "I did not do well on Saturday night, so listen to this: That will never happen again."

The crowd erupted in cheers and applause.