The United States, led by the tournament's best player Clayton Stanley, won the Olympic men's volleyball gold on Sunday beating defending champions Brazil by three sets to one in the final.

Stanley, the top scorer and server in Beijing, killed off the Brazilians at the second match point with an emblematic cross-court smash that their inspirational captain Gilberto Godoy Filho was unable to return.

"It sure hasn't sunk in yet. This was such a hard-fought battle," said William Priddy, who contributed 12 points including eight spikes to the victory.

"A gold medal in the Olympics is a huge victory for us," said team-mate Sean Rooney, referring to a campaign that was overshadowed by the killing of head coach Hugh McCutcheon's father-in-law who was stabbed to death at a tourist site here at the start of the Games.

"I think when that kind of thing happens, the guys got a good taste of what's important in life. We were crushed by that," he said.

Brazil took the first set 25-20, but the United States came back to narrowly win the next three sets 25-22, 25-21, and 25-23.

Stanley finished with 20 points, including 15 spikes, while Godoy Filho scored 14 points for Brazil and Dante Amaral 13 spikes. "They're always good, they're fast and they're tough to beat," Rooney said of the Brazilians.

"But the character of this group is so persevering, they never looked out of the match, they're just grinding and grinding and grinding."

In the decisive fourth set, the United States rallied from two points down behind the spikes of Priddy, who also teamed up with Ryan Millar and David Lee for 12 blocks.

Endres Murilo, who scored 13 for Brazil, saved a point with a drive before Stanley found himself alone in the right corner for the uncontested kill. The two teams, who were meeting for the first time in this tournament, have four Olympic titles between them.

But the Americans, who went through the tournament undefeated, had not won it since 1988 in Seoul.

Brazil started the stronger with the high-leaping Godoy Filho, Andre Heller and Amaral scoring with some crowd-pleasing kills while Stanley misfired early. But when Stanley found his groove in the second set the Americans raced to a 6-0 lead helped by his two kills and and a jump serve ace.

Brazil fought back with some inspired Godoy Filho smashes and an ace, plus effective blocking that brought them back to within one at 20-21 before a Stanley ace and two smashes got the Americans home 25-22.

The third set developed into a see-saw battle with Amaral and Stanley trading smashes until the US drew away with the help of their solid defence. Meanwhile, Russia beat Italy for the bronze medal.