Our guy broke down into tears inexplicably after the gravity-defying performance, which had him flying up into the arena while singing his new song "What Do You Mean?"
On Wednesday night, Bieber was a guest on Jimmy Fallon's "The Tonight Show," where he explained why he got so emotional, blaming it on his desperation to be liked... and a few missed cues (although we didn't notice).
"I just wasn't expecting them to support me in the way that they did," Bieber said. "Last time I was at an award show, I was booed. I think I've worked so hard on this album. I've worked so hard at just becoming the man I want to become. Stepping into situations, you just can't help but feel judged. I was just feeling judged and wanting to win so badly and just wanting to do what I love so badly that I just put everything on the line.
"That's what's so special about the emotional moment at the end," he said. "It was authentic, it was real. I was really just wanting it so bad."
Bieber also told fans that his album will drop on Nov. 13, and did a country version of "Where Are U Now." And, hey, JB might have a future in country music!
Also, um, he's really good at drumming too. I mean, we knew that, but when he went up against Questlove, it proved his skillz even more.