Rihanna and Britney Spears Wow; Eminem and Justin Bieber Win Big at Billboards

Eminem and teen idol Justin Bieber dominated the Billboard Music Awards Sunday, winning six awards each with the 38-year-old rapper taking the top honor for artist of the year.

The night got off to a rousing start when Rihanna kicked off the show with a performance of "S&M" from her 2010 fifth studio album "Loud," and was joined on stage by Britney Spears in a bondage-themed outfit.

The two then exchanged blows in a hilarious pillow fight.

Rihanna won three awards including top female and top radio artist of the year. She thanked her biggest fan devotees, who call themselves the Rihanna navy, and hailed her native Barbados.

More of pop's biggest stars took the state at the MGM Grand in Las Vegas, marking the music magazine's efforts to revive what was once an annual event following a four-year hiatus.

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Sporting his now short, spiky hair and a sparkling gold tuxedo jacket, Bieber beat singer Bruno Mars and rapper Nicki Minaj for best new artist and marveled to the audience, "I'm 17 ... every day is crazy to me because I see so many people and I get to make so many people smile."

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The Canadian pop star, who has gained a huge following of "Beliebers" through YouTube and social media websites, also won awards for top pop album, streaming artist and song, as well as social and digital media artist. He thanked "everybody who helped me get out of my home town and live my dream."

Detroit native Eminem, who released the critical and commercial success "Recovery" last year, including the hit single "Love The Way You Lie" featuring singer Rihanna, won awards for top male artist, billboard 200 album, rap artist, rap song and rap album.

The last Billboard artist of the year was Rihanna's former boyfriend Chris Brown, who pleaded guilty to assaulting her in 2009 and did not attend the awards.

Katy Perry won awards for top hot 100 artist and top digital songs, while British singer-songwriter Taio Cruz won the top hot 100 song of the year for his hit, "Dynamite."

"Need You Now," by Lady Antebellum won country song of the year. The title track from their second album introduced the group from Nashville, Tennessee to audiences worldwide and is now the most-downloaded country song ever, according to Billboard.

Taylor Swift, 21, who has swept music award shows in the past several years, won country artist of the year. She sold 1,047,000 first-week copies of her third album "Speak Now" in the United States last November, making it the fastest-selling new album in five years.

Accepting the top duo or group award for the The Black Eyed Peas, Will.i.Am singled out "technology because without technology we wouldn't be here as an industry."

Beyonce was honored with the Millennium Award for her musical influence and hailed as a role model for women.

Neil Diamond, 70, won the icon award before performing his 1969 hit, "Sweet Caroline." Other performers included Keith Urban, Nicki Minaj and singer Cee Lo Green.

U2 won the top touring award for its current "U2 360 degrees" tour, which features revolutionary staging and has become the highest-grossing tour of all time.

"You can make classic albums in your bedroom and you can play the greatest show of your life on a one-string guitar, but we just don't do that," U2 frontman Bono told the audience.

The awards, with eligibility from Feb 28, 2010 to March 1, 2011, were based on multiple factors including chart performance, album and single digital sales, touring and streaming and popularity on social media sites.