It was the first time judge has refused to vote to send act home in show’s history.
Emotional Katie ‘collapses’ onstage after forgetting her words… but survives.
Angry fans fury online claiming show was fixed to keep Katie in contest.
Last night verdict:
â€œTreyc is the better singer,â€ said Simon, â€œKatie is the more interesting singer.â€ Interest beat talent on this occasion, and Simon opted to send Treyc home.
Cheryl then refused to send either of her girls home. Dannii decided to send Katie home, so it was all down to Louis.
His heart told him to save Katie, his head told him to save Treycâ€¦ the heart one.
But mentor Cheryl Cole caused controversy by refusing to select an act to save â€“ because both singers were in her category.
Host Dermot Oâ€™Leary asked Miss Cole for her decision after Simon Cowell had chosen to save Katie.
She seemed shocked to be asked second before telling the contestants: â€˜You are both talented women. I am refusing to send anyone home.â€™
The 27-year-old added she was prepared to take the vote to deadlock by making a choice once the other judges had voted, but Mr Oâ€™Leary said it was against the rules of the show.
Dannii Minogue then opted to save Treyc, while Louis Walsh selected Katie. If Miss Cole had chosen Treyc, the girlsâ€™ fate would have been decided by the number of telephone votes each had received.
But with just three judgesâ€™ votes to go on,Treyc was the one sent home.
Mr Oâ€™Learyâ€™s refusal to let Miss Cole defer her decision until the others had voted fuelled suspicion that producers are keen to keep Katie in because she makes better television.
But a show spokesman said: â€˜Dermot was very clear. He asked Cheryl if she was refusing to vote. He told her if she refused it would simply be based on the majority. Those are the rules.â€™
It was the first time in the showâ€™s history that a judge has refused to select an act to save.
Viewers last night flooded internet forum claiming it was a ‘fix’ because X Factor producers wanted to keep Katie in the competition.
Many called for Ofcom – the media regulator – to investigate.
Photos by Â©ITV