New American Idol champion Scotty McCreery hit No.1 on the iTunes single charts on Thursday, as Fox television reported a 21 percent surge in viewers for the all country music finale of the long-running singing contest.

McCreery, 17, became the first country musician to win the Idol title and a recording contract since Carrie Underwood in 2005. The poised teen with the distinctive deep voice beat 16 year-old Lauren Alaina in the youngest Top 2 match-up in the show's 10 year history.

McCreery's newly-released single I Love You This Big went straight to the top of the iTunes singles charts, while Alaina's emotional ballad Like My Mother Does was at No.3 on on Thursday.

This is pretty wild. It is a whole lot more than I bargained for coming into this, McCreery, a former grocery store clerk from North Carolina, told reporters on Thursday. But I'm handling it well. This is my new life, so it's good.

Some 29.3 million Americans tuned in see McCreery crowned at the end of a star-studded finale on Wednesday that included performances from Lady Gaga, Beyonce, Bono and Idol judges Jennifer Lopez and Aerosmith's Steven Tyler.

According to preliminary estimates from Fox, the audience in the 18-49 age group most coveted by advertisers rose 12 percent compared to last year.

That was the first time in five years that American Idol had grown its 18-49 year old audience for the finale.

The higher numbers reflected a push by American Idol producers to attract younger contestants, and the introduction of judges Lopez and Tyler to stem a four years ratings slide.

Last year, just 24.2 million overall viewers watched the finale of American Idol, which has been a lucrative source of advertising revenue for Fox for more than seven years.

Recent Idol champions have seen dismal record sales. But with a new record label in the Universal Music Group, and Underwood's record as the top Idol earner, McCreery and his brand of country music could revive those fortunes.

I am really looking forward to getting my music out there, McCreery said on Thursday, adding that he was hoping to perform at the Country Music Association Festival in Nashville next month.

I think it's going to be a great album. I've got to pick some good songs. That's what it's all about after the show -- good songs. The fans have got me where I am right now, but now I have to get out the music they want to hear.

Country music is me, it's what I grew up with, it's what I do, he added. I have done all the work on 'Idol' and now it's time for the real job to start.

Fox is a unit of News Corp; Universal Music is a unit of Vivendi; iTunes is owned by Apple Inc..

(Reporting by Jill Serjeant, editing by Christine Kearney)