US President Barack Obama on Tuesday burned off his election-day nerves in traditional fashion, with a game of basketball with close friends, as millions of Americans went to the polls.

US President Barack Obama on Tuesday burned off his election-day nerves in traditional fashion, with a game of basketball with close friends, as millions of Americans went to the polls.

Obama gathered an all-star line-up including Chicago Bulls great Scottie Pippen, his brother-in-law Craig Robinson, who is a college basketball coach, White House chef Sam Kass and Education Secretary Arne Duncan.

The president started his election day tradition during his 2008 primary run against Democratic foe Hillary Clinton, as a way to burn off the long hours between the end of the campaign and the counting of votes.

Alexi Giannoulias, a former Illinois state treasurer who also played in the game, said two five-player teams played four 12-minute quarters in the game, and swapped out periodically with substitutes.

He said the president, who is known to be a competitive player who trash talks teammates and opponents alike, led his team to victory, though wouldn't say how many points Obama posted.

After the game, in an athletic center near the president's Kenwood neighborhood in Chicago, Obama returned to his house, where he was to eat dinner with his family and wait for the results to pour in.

He and his wife Michelle were due to be joined by their daughters, Malia, 14 and Sasha, 11, for election night events, after they finished their school day at the private Sidwell Friends school in Washington.