Simon Cowell's group Alex and Sierra performed 2 songs last night on The X Factor. On Dec. 5, 2013, the duo reached #1 on iTunes with Say Something. Alex and Sierra also took the #13 spot with the other song they sang last night, Say My Name. This is the highest anyone on The X Factor USA has ever ranked for a performance song.Other X Factor acts who ranked high on iTunes this week are Restless Road and Jeff Gutt. A Great Big World and Christina Aguilera's version of Say Something is currently at #3 on iTunes.A Great Big World tweeted to Alex and Sierra, WOW! Huge congrats to @alexandsierra3 for your version of Say Something from @TheXFactorUSA reaching #1 on iTunes!!Even though Alex and Sierra's Say Something performance was the highlight of last night's show, Sierra was actually very sick. Sierra says, I can say it now since we've already performed and it's not an excuse. I'm really sick. I got one of those shots in my bum. Alex adds, That's why she's talking at 7 million miles per hour! Nobody had any idea that she was so sick which just shows how professional Sierra is already.