OS ANGELES (AP) — Lady Gaga wasn't the most nominated entertainer at American Music Awards, but she was certainly the most compelling performer at Sunday's show.

Wearing a Vulcan-inspired headdress and vest filled with lights, the 23-year-old singer performed a medley of songs from her new album, "The Fame Monster," due in stores next week. She used her microphone to break into a class case, where a grand piano sat waiting. It caught fire when she sat down to play.

She came into the American Music Awards with three nominations, including artist of the year. Also up for the night's highest honor are Michael Jackson, Taylor Swift, Kings of Leon and Eminem.

With five nominations, Jackson was poised to become the American Music Awards winningest posthumous artist. He was named favorite male soul/R&B artist and his 2003 greatest-hits album, "Number Ones," won best soul/R&B and pop/rock album and favorite pop/rock male.

Jermaine Jackson accepted both awards on his brother's behalf, and donned a white glittery glove in tribute.

Swift was the night's most nominated with six nods. She was named favorite female pop/rock artist and her album, "Fearless," won best country album.

The American Music Awards honor the year's top-selling artists in eight popular genres. But even more than awards, the AMAs are about performances, and they came back to back to back Sunday.

The Black Eyed Peas, voted favorite pop/rock band, energized the crowd when they performed two of the year's most popular hits: "I Got A Feeling" and "Boom Boom Pow."

Dancers wearing outfits made from stereo speakers shared the stage with Fergie, Taboo, apl.de.ap and will.i.am, who wore a pompadour wig. The high-energy medley melted into a Nirvana sample at the end, with will.i.am rocking on guitar.

Rihanna returned to the AMA stage Sunday, sporting blonde hair, a skintight white bodysuit and a tattoo down the front of her neck that read "Rated R," the name of her new album, out next week.

Janet Jackson opened the show with a medley of some of the biggest hits from her long career — all tracks that appear on her new greatest-hits collection, also called "Number Ones."

Alicia Keys and Jay-Z dueted on their ode to New York City. Shakira was flanked by a dozen dancers in tiny black bodysuits as she sang her new single. Kelly Clarkson performed a stripped down version of her hit "Already Gone," backed by a string quartet.

Jennifer Lopez added a boxing motif to her dance-filled performance, but she slipped during a tricky move and landed on her bottom.

More than a dozen artists were expected to take the stage Sunday, including Adam Lambert and Green Day, which won favorite alternative artist.