Mentor and X Factor judge Louis Walsh surprised viewers when he refused to vote on his own acts in a sing-off.
He was being forced to make a decision as both his boy bands fell into the bottom two.
But Louis refused to cast his vote on whether District3 or Union J should be kicked off the show.
He told the show's host, Dermot O'Leary: "I am not voting. I am not sending any of these acts home. No way! I'll leave it up to the other two judges. I cannot judge between my two acts. I love both of them."
But it took just two judges' votes to see Distict3 axed from the show.
Gary Barlow told the audience: "When I saw both of these acts in the bottom two I thought this would quite simple, because in the past I feel like District3 have always really sung well in this competition. I thought in a sing-off they would beat these guys easily.
"The shame is that tonight was one of your worst vocal performances to date. I am so disappointed."
He said to Union J: "Although there was less harmony in your performance, I thought you wanted it that bit more."
And he sent District3 packing.
But it was judge Nicole Scherzinger who cast the vote that meant the end of the road for the trio.
She said: "For you District3, having a bad day of harmony is other people having a good day. You should be very proud of that. Boys, you have my heart, you really do. The group that I think is more mature, and a little bit more ready for this right now is Union J."
And she sealed District3's fate by voting them off.
After the vote had been decided Tulisa Contostavlos added: "I think their performances were amazing in different ways. One is an R&B harmony group, the other is more of a commercial boy band. I have a deep connection with District3. My heart has been with them since the beginning. I would have saved District3."
Afterwards Greg West, from District3 said: "It is the most gutting feeling in the world. "Performing every Saturday night has just been the most phenomenal feeling. We hope that's not the last."
When Dermot asked Louis what went wrong, he replied: "They just didn't get enough votes, but I hope they get a record deal. They are a ready made pop act.
"Maybe the two boy bands were splitting the vote."