Abi Alton was voted off the X Factor by majority vote after judge Nicole Scherzinger said: "I refuse to choose between my girls".
The singer found herself in the bottom two alongside Hannah Barrett.
Judge Gary Barlow admitted he was surprised by the public's choice, saying he was "confused". He added: "I don't know how these singers are ending up in the bottom two."
Hannah performed Wrecking Ball by Miley Cyrus while Abi chose Lego House by Ed Sheeran.
Before voting off Abi, Gary praised her: "Abi, I have loved your performances but tonight you touched me emotionally for the first time."
He added: "Hannah - don't change anything, you are brilliant just as you are."
Sharon Osbourne said she would also be sending Abi home, adding that it was "frustrating" that "now you show us your passion".
Sharon told Abi: "You are a talented singer-song writer. I haven't seen you this passionate since the auditions."
Gary and Sharon's votes meant that Abi would leave the show. When asked who he would have voted off, Louis Walsh said that he too would have chosen Abi.
Abi said: "I never in a million and one years thought that I would get this far. I've had the time of my life. I've met the most amazing people. I would never change it so thank you."
Presenter Dermot O'Leary praised her as "so unique, so original".
All four judges heaped praise on Rough Copy's performance, telling presenter Dermot that they thought the three-piece boy band had 'nailed it' with their Ray Charles number.
The judges said they were also particularly impressed with Sam Bailey's dazzling performance.