Of the four females under age 30 to perform on 'X Factor' on Thursday night, 21-year-old rugby player Caitlin Koch left the biggest impression on judge Simon Cowell. The Buffalo, N.Y. native sang 'Will You Still Love Me Tomorrow' by the late Amy Winehouse and delivered one of the night's most professional and memorable performances.

Cowell and his team of advisers praised her tone and pitch. Unlike the other three judges, he wasn't joined by a superstar from the pop world. Mariah Carey was scheduled to help him judge the talent, but Hurricane Irene forced the cancellation of her flight.

The first two female contestants weren't as strong, but neither torpedoed her chances of moving forward after the other four perform on Sunday. Simone Battle sang 'Help!' by the Beatles, and although her voice cracked multiple times due to nerves, Cowell said he thought it added to the emotion of the performance. As she had in previous episodes, the 22-year-old once again seemed confident (wearing a back leotard and mesh skirt) and once again showed flaws. Last week she forgot the words, but still managed to move on.

Tucson, Ariz. native Tora Woloshin was the second female to sing, and Cowell chose the Rolling Stones' 'Satisfaction.' Before singing, the 22-year-old blonde was terrified she'd forget the words. She did take a few liberties, but otherwise put together a passable performance in an outfit that seemed sponsored by Hot Topic. Cowell enjoyed it, but said there was something missing about the heavily tattooed, daytime auto-technician.

The night's final singer was 14-year-old Drew Ryniewicz. The Chino Valley, Ariz. born singer looked terrified singing Roxette's 'It Must Have Been Love,' but delivered. Cowell raved about her tone and pitch and looked genuinely giddy to have such a young talent on his team.

We'll find out which, if any, of these singers will move on after the other 16 contestants perform on Sunday. Four from each group will move on to next week's live rounds.

Watch the Girls Perform for Simon Cowell on 'X Factor'