Jahmene Douglas was the contestant on the receiving end of the praise, as the remaining hopefuls once again performed two songs each to try to battle their way into the final.
The shy former supermarket worker opted for Whitney Houston's I Look To You as his first song - one that was purely his choice and meant something special.
Having previously struggled against emotion to sing the track at his brother's funeral, he was determined to give it his all and reduced his mentor Nicole to tears in the process.
"I surrender," Nicole said, throwing her hands up as she tried and failed not to cry.
"I could sit here and say you're vocally the strongest, the most soulful, the most dynamic singer ... But that's not what it's about - when what's so special about you is where that voice, and where that spirit, and where that soul comes from."
That was so emotional - I know every lyric in that song meant so much to you. And there's no way you're going to go back to Asda, man.
It was Jahmene's second song - Etta James's At Last, which was his first audition song - that drew the 'jah-mazing' praise though.
Louis Walsh's use of the word drew raised eyebrows from Gary Barlow, but then the Take That star simply had to concur - much to Nicole's delight.
"Get outta here!" she then beamed, to laughter from the audience.
"Get outta here, taking the mick out of all of us. That was ... That was ... I'll say it - jah-mazing!"
The X Factor's resident 'credible artist' James Arthur also impressed the panel with his song choices - U2's One and Frankie Goes to Hollywood's The Power Of Love.
"You come out ready for attack each week, knocking the opponents down one by one," Gary said.
Union J were deemed to have grown-up during the course of the competition and were praised for their mature performances - even if they are still young enough to get away with wearing onesies and somehow talk their mentor Louis into trying one on for size!
Not only do you look sch-amazing in a green onesie, but you are like a fifth member of this band ...
"You are a bomb-diggity mentor," Nicole told Louis. "You chose brilliant songs for them this week."
They opted to perform Beneath Your Beautiful by Labyrinth and Emeli Sandé and then Lonestar's I'm Already There, with Louis continuing to bill them as the next big boyband.
But for Christopher Maloney, there was a mixed reception throughout the night.
His first performance, a Josh Groban-inspired take on You Raise Me Up, was dedicated to his biggest fan - his often-mentioned nan - and it went down well with the judges.
"I really enjoyed that performance. No buts - I think you've picked the perfect song choice," Tulisa, one of his harshest critics, said.
But Chris's second song, Michael Bublé's Just Haven't Met You Yet, was a different story.
"Oh, Chris ... It is the semi-finals and I don't think that was your strongest performance, my love," Nicole said, blaming his mentor for choosing the wrong song.
"We're pointing out the type of artist he's going to be - Josh Groban, Michael Bublé ... That's his lane right there," Gary explained.
"That was kinda back to the karaoke thing for me," Louis chimed in. "I don't think you're Michael Bublé, but you are who you are and I love you doing the old songs."
To find out who has made it to the final and who will be exiting the competition, tune in to Sunday's X Factor results show on UTV at 8pm.