In what could signal a generational shift in the country music world, an elated [artist id="1933910"]Carrie Underwood[/artist] became the first female since 2000 to win the Entertainer of the Year award on Sunday night at the Academy of Country Music Awards in Las Vegas.

"I've had a lot of good moments in the last four years. This one takes the cake!" Underwood said, as her voice cracked and she teared up before thrusting the award in the air in celebration and giving a shout-out to hockey-playing boyfriend Mike Fisher. "I don't know what to say! I got nothing."

It was a big night for the former "American Idol" winner, who also repeated last year's win as Top Female Vocalist.

For the second year in a row, the Entertainer honor was determined by a popular vote during the broadcast, unlike past years, when the award was given out to the performer who sold the most concert tickets in the previous 12 months. Underwood wrested the top prize from perennial winner Kenny Chesney -- who has taken it home the past four years -- and became only the seventh woman to win it since the show launched almost four decades ago. The significance of joining a list of female winners that includes Dolly Parton, Loretta Lynn, Shania Twain and the Dixie Chicks was not lost on the 26-year-old.

"I accepted that award on behalf of myself and my fans, but also on behalf of other women who came before me that kicked butt but never got the recognition they deserved," Underwood said backstage, according to The Associated Press. "I can't wait [for] the day, which I hope is in the very near future, where having females in the category is no big deal whatsoever."

Fellow young country phenomenon [artist id="2389485"]Taylor Swift[/artist] beat out such heavy hitters as George Strait and Montgomery Gentry -- not to mention Underwood -- for Album of the Year for her smash, Fearless. Swift also performed on the show, playing "You're Not Sorry" after magician David Copperfield conjured her on the stage. Underwood performed "I Told You So," wearing a giant burgundy dress that nearly overwhelmed the stage. Miley Cyrus, another young country star who could be having her day at the ACMs in the future, was there to play her current single, "Climb."

"I think a lot of people who know me know that if I talk to you for more than five minutes, I'm probably going to write a song about you, so, that being said, I'd like to thank all the characters in my songs: Abigail, Hey Stephen, Tim McGraw and Romeo," Swift, 19, said about her autobiographical writing style. "The fact that you can write songs in your bedroom about your feelings and boys, and can win album of the year at the ACMs -- I just didn't think that was possible."

Swift, who later said that she had labored obsessively for two years over Fearless,

also won an honorary ACM Crystal Milestone Award for helping to bring more young fans to country music.

Other winners included Brad Paisley for Top Male Vocalist; "Dancing with the Stars" winner Julianne Hough, who snagged Best New Artist in a fan-voted category; and Sugarland, who beat out Brooks & Dunn for the Top Vocal Duo award, breaking the team's 14-year stranglehold on the category. Rascal Flatts -- who were covered by [article id="1608238"]Danny Gokey on "American Idol"[/article] last week -- won Top Vocal Group and the Zac Brown Band took the Top New Vocal Duo or Group award.