After suffering through weeks of mockery from L.A. Reid for not actually, you know, singing in harmony, the girls of Fifth Harmony finally got their shot at redemption on tonight's (Dec. 5) episode of 'X Factor.'

After finishing their first number of the night, a cover of Adele's 'Set Fire to the Rain,' and being told by Reid that "they should have named you Fifth Unison," the ladies returned with what might have been their best performance of the entire competition: A spirited version of Demi Lovato's 'Give Your Heart a Break.'

The song was chosen for the group by the fans, and they seem to know what they're doing -- for the first time in recent memory, each member of Fifth Harmony looked and sounded completely comfortable with the material, and the stage presentation (also chosen by the fans) highlighted their individuality while giving the performance a splash of color. And yes, they did finally sing in harmony, showcasing their vocal blend between trips to the solo spotlight for each member.

The 'X Factor' judges rewarded them for a job well done when it came time to hand out the verdicts, with an enthusiastic Reid first in line to make nice. "Unbelievable! I actually heard harmony, and it was really good," he laughed. "For me, that was your very, very best performance."

"This is what we've been trying to do -- to show that you're a legitimate girl group," pointed out their mentor, Simon Cowell. "The show would not be the same without you."

But the highest praise of all came from Lovato, who told the ladies, "I think this song should have been your song. You sounded so beautiful on it...better than the original. It was energetic, it was fun -- I think that Simon actually did a good job this week."