Credit: Michael Becker/©2013 Fox Broadcasting Co.

We guess Sierra Deaton of The X Factor’s dynamic duo Alex & Sierra shouldn’t have worried if she and boyfriend Alex Kinsey could recreate the magic of last week. Their duet of Sara Bareilles’s “Gravity” has hit number two on iTunes less than 24 hours after they debuted the number on the December 11 Live Show, according to The Hollywood Reporter.

The good news comes on the heels of the couple’s stunning success of last week; their take on “Say Something” by A Great Big World claimed the number one spot on the iTunes chart the morning after they first sang it live on The X Factor.

Alex & Sierra’s mentor, judge Simon Cowell, couldn’t seem more thrilled with his team’s popularity: “Alex and Sierra are number 1 again on iTunes! Thanks to everyone who has bought it,” he tweeted December 12.

With the remaining X Factor contestants gearing up for next week’s two-part finale, Alex & Sierra’s market success would seem to indicate a likely win for the couple. They’re the team to beat according to two of the couple’s fellow X Factor contestants.

“I think Alex & Sierra are definitely one of the front-runners of this competition,” Colton Pack of X Factor trio Restless Road told Wetpaint Entertainment in an exclusive interview. “They have such a unique sound and there’s no one like them out there right now. America really loves them and loves their story.”

Fellow competitor Jeff Gutt agreed, exclusively telling Wetpaint Entertainment Alex & Sierra “have a lot of support and just in general are doing really well.”

Despite their success with remaking already popular songs, both Sierra and Alex stress they’re more than just a cover band.

“A 100 percent we want to be putting out our own music,” Sierra tells Wetpaint Entertainment. “We want to prove we’re songwriters too.”

We can hardly wait to hear what these two rising stars have in store!

Sources: The Hollywood Reporter, Simon Cowell on Twitter

Elisabeth Kramer is an Assistant Editor at Wetpaint Entertainment and our resident Downton Abbey expert. Follow her on Twitter and Google+!