The 1996 Atlanta Olympic champions will meet either Brazil or Argentina in the gold medal match in Beijing on Saturday.

Olubayo Adefemi opened the scoring in the 17th minute and Chinedu Ogbuke Obasi netted a brace before Chibuzor Okonkwo hammered the final nail in Belgium's coffin.

Substitute Laurent Ciman pulled one back in the dying minutes but it was too little too late.

Nigeria came out firing on all cylinders with Belgian goalkeeper Logan Bailly called into action twice in the opening minute, parrying a tricky cross then getting down low to save a shot from captain Victor Obinna.

Belgium, who had never been this far at an Olympics before, had their first chance on five minutes when Lille striker Kevin Mirallas whipped off a left foot strike that slid well wide.

The Nigerians, with the inherited experience of six Olympics and one gold medal, pressed the attack and a sustained period of pressure resulted in the opener.

The Belgian defence was at fault, failing to clear the ball and it fell to Adefemi inside the box and he slotted it underneath the diving Bailly.

Chances came thick and fast with Belgium's Sevilla frontman Tom De Bul going close just minutes later as the action went from end to end.

Hertha Berlin forward Solomon Okoronkwo almost made it 2-0 ten minutes before the break when his pace took him past a defender but his drive whistled past the post.

Belgium were almost made to pay the price again soon after the restart when a misunderstanding between two defenders saw a pass go astray, but Peter Odemwingie wasn't able to capitalise.

At the other end, Ajax midfielder Jan Vertonghen struck a beautiful volley after connecting perfectly with a lofted corner kick, only to see Nigerian keeper Ambruse Vanzekin somehow keep it out.

The Africans got the all-important second goal after 59 minutes, but they were fortunate as Ogbuke Obasi looked to be offside when Everton's Victor Anichebe fed him the ball.

He put it in the net with the outside of his left boot and Chilean referee Pablo Pozo allowed it to stand.

Anichebe was playing well, causing the defence problems, but Toffees boss David Moyes won't have been impressed when he missed an open goal from three yards out.

The match was put beyond doubt with 18 minutes remaining when Obinna laid off the ball to a rampaging Ogbuke Obasi who hit a powerful strike from 25 yards that gave Bailly no chance.