Britney Spears' comeback performance at a Las Vegas awards show was pummeled by critics on Monday, with US media lambasting her lip-synced display as "lackluster, bumbling and underwhelming."

Troubled pop princess Spears had been hoping to use the MTV Video Music Awards as a prime-time platform to showcase her new single "Gimme More" from her first album in four years.

But Spears, who appeared on stage in high heels and a skimpy outfit, singularly failed to wow critics with her much-hyped performance.

Under a headline "Britney's Comeback Bust," People Magazine in its online edition said Spears looked in need of more practice.

"Britney Spears kicked off Sunday's MTV Video Music Awards at the Palms in Las Vegas with a bad costume and a lackluster performance of her latest song "Gimme More," that could have used a lot more rehearsal," People commented.

Hip-hop star Akon told People that Spears' had appeared nervous.

"That could have been better," he said. "She needed to focus more. She looked nervous and I think the pressure got to her."

Other reviews were less restrained.

In a withering put-down, the Los Angeles Times reviewer said Spears "looked more like Edie Sedgwick in the post-lobotomy scenes of the underground movie 'Ciao, Manhattan.'"

Under the headline "Britney's Bumbling Comeback," the paper's online edition asked: "When will we be sick of watching this spectacle?"

"Never more than a passable singer, Spears was once a shockingly charismatic physical presence: she was youthful freedom personified, her gorgeous form and defiant beauty absolutely Nabokovian," the review said.

"But the fire has apparently gone out of her loins."

The Washington Post reviewer said simply: "Britney was not ready for prime time," describing Spears as "underwhelming."

"An out-of-shape Spears moved tentatively around the stage, getting totally outgrooved by her backup dancers and badly lip-syncing her way through the song whose main lyric was "Gimme, gimme, gimme, gimme," the Post said.

Several critics took aim at Spears' raunchy attire. The Boston Globe commented: "Clad in a black and silver glitter bikini, Spears trudged through her paces as if she were at a dress rehearsal as opposed to the actual show, teetering around on heels that seemed to make her nervous."

Many reports gleefully reported the comments of comedian Sarah Silverman, who savaged Spears on stage immediately after the performance.

"She is amazing," Silverman said. "She is 25 years old and has already accomplished everything she is going to accomplish in her life."

(Agencies via CRI.cn September 11, 2007)