It was a nail-biting night for Alex & Sierra, who went into Wednesday's performance show as the favorites

The X Factor ended its season on a star-studded note on Thursday that saw amazing vocals, emotions running high and tears of joy.

Jeff Gutt, Carlito Olivero and Alex & Sierra all delivered memorable performances on Wednesday night, but it was the adorable boyfriend-girlfriend duo of Alex Kinsey and Sierra Deaton who scored the most votes and won the $1 million recording contract.

It was a nail-biting night for Alex & Sierra, who went into Wednesday’s performance show as the favorites, but were challenged for the X Factor crown by dark-horse Gutt, whose performance of “Dream On” had the duo’s mentor, Simon Cowell worried that the 37-year-old single dad could win the competition.

“The minute Jeff sang that song, I thought, ‘We’re in trouble,’ ” Cowell told PEOPLE after the show on Wednesday night.

A little more than an hour into the show, it was announced that Olivero was in third place. “I’m blessed. I’m happy,” he said. “I’ve worked so hard to get here and we came in third place, baby! I cannot be mad. I love everybody at home.”

Then, just before the end of the broadcast, Alex & Sierra were declared the winners. “We’re speechless,” Alex said, “I don’t even know … this is incredible. Thank you everybody that’s voted.”

“Thank you so much for getting us here and thanks for not making fun of my weird faces all of the time,” Sierra added.

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Cowell also spoke about their win: “I feel like Christmas just came early. Jeff, big respect … You did brilliantly in the finale. But my heart was with these guys. Thank you, America.”

The duo were left in shock over their win. Overwhelmed, they struggled to perform “Say Something” after hearing the news – but the crowd was understandably forgiving.