WATCH: Casey Abrams Proves Mentors Wrong in 'American Idol' Triumph

"American Idol" contestant Casey Abrams went against the grain, singing Nat King Cole's classic tune "Nature Boy" on Wednesday's episode, even after Will.i.am and Jimmy Iovine suggested he go a different direction.

Casey had his heart set on performing Nat King Cole's ballad because he felt it fit his style the best, but had second thoughts when Will.i.am and Jimmy adamantly prodded him to try a more lively song.

"This show is like a hurricane," said Jimmy. "If you really wisper, ain't nobody gonna hear you."

Jimmy seemed displeased when Casey decided to follow his gut instincts, saying, "If you want to win this competition you need to take the help at this point, and Casey chose not to. So, he better be right."

Right he was when he took the stage and blew away the judges.

Jennifer Lopez gushed, "What's beautiful about this season is that we have gospel, rock, country, pop, jazz. We have all of it."

"I don't think we've ever had anybody exactly like you ever," Randy Jackson raved. "It makes me proud to sit here and judge artists as well as pop stars."

Casey was almost brought to tears during his post-performance interview saying, "I feel, like, a sense of accomplishment. I feel like people were against me and I stood my ground and I did something that's never been done."

Watch "American Idol" Wednesdays and Thursdays on FOX.