WASHINGTON — There was a familiar voice behind the microphone during the Duke-Georgetown basketball game — that of Barack Obama.

The president, attending as a fan, provided about seven minutes of nationally televised hoops commentary in the second half of Saturday's matchup of two top 10 teams at the Verizon Center near the White House.

The president shook hands with several fans as he entered the arena, and enjoyed the game from a front-row seat, not the luxury suites that top government officials sometimes prefer. Those with him included Vice President Joe Biden, White House senior adviser David Axelrod and White House spokesman Robert Gibbs.

Shortly after the second half began, the president was seated between CBS announcers Verne Lundquist and Clark Kellogg. Obama, an avid fan of the sport who often plays pickup basketball games, seemed to impress the pair.

After Obama described a spin move and basket by one player, Kellogg told him he could handle the job of announcing.

"After retirement, I'm coming after your job, Clark," Obama replied. "I'm just letting you know. So you either have three more years or seven more years," he said, referring to the possibility that he might be re-elected to a second term.

At another point, CBS aired tape of a pickup game Obama played during the 2008 presidential campaign, including a missed left-handed layup. That prompted Lundquist to ask Obama if he has problems dribbling to his right.

"I went to the Republican House caucus just yesterday to prove that I could go to my right once in a while," Obama joked, referring to a televised session Friday when the president attended a House GOP retreat in Baltimore.

The president munched on popcorn and occasionally used his Blackberry. A Columbia University graduate, he revealed no preference for either team, despite sitting among a throng of wildly cheering Georgetown fans, including some who were shirtless, smeared in blue and gray body paint and wearing wigs.

After a referee made a call that went against Georgetown, an obscene chant was cut short after one student admonished another, "Dude, the president of the United States is right there."

Obama told the CBS announcers that his job keeps him too busy to watch a full game on TV during the regular season. But when it comes to NCAA tournament, he said he watches all the Final Four games.

Obama departed with about a minute left in the game, which seventh-ranked Georgetown won over No. 8 Duke 89-77. Nearby students chanted "USA, USA" as he exited waving.

Duke coach Mike Krzyzewski and Georgetown coach John Thompson III said players were definitely aware of Obama's presence, which added to the high level of energy in the game.

"We were more nervous about the guys sitting on the other bench," Thompson said. But "it's good to play well when he was here."

Security for the game was intensified, with fans having to pass through metal detectors, cars being searched as they entered the building's garage, and a large number of security agents in the arena.

Duke and Georgetown are using their game to launch an initiative to raise money for children in refugee camps in the Darfur region of Sudan.

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Associated Press Sports Writer Joseph White contributed to this report.