Speaking on an episode of The Jonathan Ross Show that is scheduled to air tonight, Barlow made it clear that he would not have had Clark in his final three.
"Come on Nicole, you've got ears," said the Take That star as they discussed the Essex-born contestant.
"His voice has grown and he's not a big ballad singer," replied Scherzinger, defending her act. "He's a great performer."
Clark joins James Arthur and Jahmene Douglas in the Boys category, mentored by Scherzinger. The eccentric singer was overcome with emotion upon being told he had made it through to the Live Shows, and clips of his over the top reaction have become popular online.
On Friday (October 5), Louis Walsh revealed that he agreed with Scherzinger's decision, telling Digital Spy that he would "definitely" have put Clark through because "he's a household name already."
He added: "Not everybody is going to love you, but that's okay. You are never going to please everybody."
Barlow also told Ross that despite minor disagreements over acts, all four judges do get on well off-screen.
"I think we're all quite protective of each other although the gloves do come off on a Saturday night," he explained.
"We have a go at each other, we have a few jokes and we pick on each other, but none of it comes off the stage. It's all for the fun of the show."
The X Factor Live Shows start tonight at 8pm on ITV1. The Jonathan Ross Show, featuring Gary Barlow, Nicole Scherzinger, Stephen Fry and Taylor Swift follows at 10.20pm.