Moving onto the second round of competition, the 32-year-old crooner said he's been looking forward to giving the judges "even more of myself" with a cover of "Lately" by Stevie Wonder, who he revealed is one of his musical idols.
Manuel belted out a beautiful rendition of the iconic ballad, which served as a pitch-perfect showcase for his range and vocal artistry, and brought the audience -- and judge Mel B -- to their feet.
"I just think that you are amazing," the former Spice Girls star marveled. "It's just flawless. I wouldn't change a thing."
While Mel B and Heidi Klum had nothing but praise for the young crooner, Simon Cowell said he was underwhelmed by the performance, namely because of his song choice.
"I think you missed the point by singing a Stevie Wonder song," Cowell explained. "There's no better way of singing that song than how Stevie Wonder sings it… I thought it was quite annoying."
Cowell then asked Manuel to give him 30 seconds of the song he sang during his audition, Whitney Houston's powerful ballad "I Have Nothing," and without missing a beat, Manuel delivered an exceptional rendition with no musical accompaniment, showing off his spectacular ability to hit some serious high notes.
Manuel's astonishing follow-up performance earned a standing ovation from the entire panel, and Cowell's belief in the promising contestant was reaffirmed.
"Even from what I just heard there, honestly, you are one of the best singers in the competition," Cowell said. "So, thank you."
"You hit notes that I could only dream of," the GRAMMY-winning singer marveled.
"I was always taught that you have to be ready at every situation, because you never know when opportunity is going to knock on your door," he continued. "Simon said to you, 'Give me something a capella,' and you didn't flinch. You just gave an incredible rendition."
After teasing Manuel a bit by hovering his hand over the coveted Golden Buzzer
, and roiling up the crowd into a fervor, Seal slammed his hand down, sending a rain of golden confetti showering down on Manuel.
"It's very rare to see talent like that," Seal told the excited singer, after joining him on stage and giving him a hug.
The moment is even bigger than it appeared on the surface for Manuel, who has been struggling with his dreams since he was a teenager.
As Manuel explained to the judges during his audition, when he was 14, he was signed to a record label as a rapper who went by the name "Little Johnny." He went from performing as an opening act for major artists to getting dropped by his label and having to return home to live with his parents.
Now, he's moving on to the live rounds of the America's Got Talent competition
, where he will try to win over the hearts of viewers across the nation with his impressive voice.