Here's what the judges had to say:
Rachel - 'Lost In Music'
Louis: "Rachel, after last week's outstanding performance, tonight I'm not sure about the song choice and if I'm honest it was pretty average."
Cheryl: "I don't know what happened at the beginning. I think first on is hard for everyone and it was probably just nerves. I think it was the perfect song for you and it brought everyone up."
Simon: "Everything I loved about you when I first saw you disappeared tonight. It was clumsy and gimmicky and you looked uncomfortable. It was arguably one of your worst performances. It's not a singer's song, it's a track, so therefore with all the millions of songs you could have chosen from that era, it was thrown away."
Dannii: "I knew Simon would hate it. You messed up at the start but it happens to all singers around the world. It was a great performance and the audience loved it. You will see tonight how hard disco is. Disco is a very hard week."
Austin - 'Wishing On A Star'
Louis: "Simon did pick a difficult song but I did think it was very good. There's a problem with you and the public, I don't think you're connecting."
Dannii: "You have made it, you are here on the stage with six sexy sirens! The vocals were great but all I want you to do is to just enjoy it. That's maybe what Louis was getting at."
Cheryl: "The song was stunning. Brian, beautiful choreography! The thing is, Will Young was right, you think far too much about what your voice is doing rather than with the emotion. I think that's the only thing missing. There's a likeability missing."
Simon: "I know why you were distracted, because you have the hots for one of the dancers, don't you? Who is it? I know it's true! I've probably got you in trouble with your girlfriend now but who cares! Listen, I don't think you've had enough credit so far for what a good singer you are. I still don't think we've heard the best of you yet but I hope you survive this week and continue to do well."
Diana - 'Call Me'
Louis: "I don't think Blondie was disco, by the way, Diana, and I'd like to see you dancing a bit."
Dannii: "I agree with Louis, Diana and disco should not mix, but you were the hottest disco dolly ever! Loved you belting out the choruses!"
Simon: "You were very lucky you couldn't see what was going on behind you. That was one of the worst routines I've ever seen in my life. But beyond the chaos, you managed to yet again make it a beautiful piece of work. Best performance so far and you are proving to be a very adaptable singer."
Cheryl: "You just get better and better every week. Louis, it's not a dance competition, it's a singing competition."
Daniel - 'Don't Leave Me This Way'
Louis: "Daniel, I know I saved you last week, but tonight’s a completely different story. I hated it. You are the perfect cruise ship singer."
Cheryl: "One piece of advice I will give you Daniel, is to stop taking the criticism to heart so much. I would far rather see you having the time of your life and hitting a few bum notes than having a terrible time and getting it perfect. Just enjoy it a bit more. Let it go!"
Simon: "It was arguably one of the worst performances we have had on this show and I say that because of the ghastly choreography, the winking and the interaction with the dancers. This has got to stop."
Dannii: "That's not even funny anymore. I thought it suited you so much. Your voice fitted so well in that. I was worried about disco week for you but that suited you."
Laura - 'Somebody Else's Guy'
Louis: "Laura, last week was incredible, tonight you picked a very difficult song and you got it perfect. You belted it out!"
Dannii: "You shouldn't be able to do that at your age. That was magnificent! That's a really hard song and you made it effortless."
Simon: "Laura, once again, outstanding vocals. One criticism, I don't think you're connecting the way you look and the way you perform and as an all round artist you need the whole package. I think you need to spend more time on your image. Diana seems to be getting stronger. You need to feel more comfortable, be more quirky…"
Cheryl: "Hang on… Laura, are you happy with how you look?"
Cheryl: "I'm happy with the way you look! There we go! This is one of the hardest weeks for you but it was one of the most fun performances from you. Dancing around isn't the thing you feel most comfortable with but we worked hard at it and I think you did brilliantly!"
Eoghan - 'Could It Be Magic'
Louis: "I can't find anything to say, you have the cute factor! Every mother is going to vote for you. I still think you will be in the final."
Dannii: "Disco isn't even an era that you would know about but you followed through with what's in now, High School Musical, Britannia High.You made that current."
Cheryl: "Last week was: 'Wow!' But this week, it went back to cute for me. This week it was very High School Musical. I think you looked a bit uncomfortable up there."
Simon: "I didn't see any discomfort whatsoever. It was a brilliant song choice for you. Two things, a) you want to entertain and b) you have guts, which is important in a show like this."
Ruth - 'No More Tears (Enough Is Enough)'
Louis: "I think you picked the hardest song. You're a fighter and you want to stay in this competition. There are four other girls in this competition though and I think they're better."
Cheryl: "There's always a real belief to your performance. You give off a belief but I didn't think you believed it so much tonight. The thing that amazes me is that you're not in your own country, you don't have a region voting for you but people are keeping you in for your talent."
Simon: "I can't argue with the passion there. I felt like I was being dumped! I don't want to fall out with you! Brilliant song choice but I kind of agree with the guys, I don't know if you are the best but no one tries harder than you and I thought you performed it incredibly well. You're a fighter and I hope the public keep you in after that performance."
Dannii: "That was brilliant.You have not had a voice this week and we had to take the key down. That top note was brilliant.You did fantastically!"
Alexandra - 'On The Radio'
Louis: "Alexandra, I loved the outfit, loved the choreography! Last week was amazing and tonight you picked a song by Donna Summer, not many can sing a Donna Summer song. I loved everything."
Dannii: "The big, big stars are the ones that can tour and do all that. Every week you show us it would be amazing to come see you on tour."
Simon: "Most performed, most improved performer in last two weeks. Something has now clicked in you! Once again it was a great, great performance."
Cheryl: "You said you had to get stronger and stronger, and that's what you do. You never let me down and what's clicked is that you're starting to believe it. Well done!"
JLS - 'Working My Way Back To You'
Dannii: "Guys, that song suited you so well! That was the performance that we could see was going to come when you first walked into the auditions. That was brilliant! One thing I will say is, don’t get overshadowed by the backing vocals each week."
Cheryl: "I would say that that performance has cemented you. You are the best group we've ever had on the X Factor. It's always good to know when people should take the lead and Aston, you did a great job!"
Simon: "Guys, you’re back in the race. Picking up from what Cheryl said, it's a sign of incredible maturity that you let this happen tonight. Tonight was the first time I could see you getting in the final and being a recoding artist. It was your best performance so far."
Louis: "You're just going to get better and better each week. Aston, great lead vocals. Best band ever in the X Factor."