FREETOWN -- George Weah, playing his first match since quitting and then returning to the international game, scored a vital goal on Saturday as Liberia beat Sierra Leone 1-0 to keep alive their World Cup hopes.

The result puts Liberia back at the top of African group B with 15 points after their eighth and final match.

Nigeria, on 13 points, require a home win against Ghana in two weeks' time to clinch the group's single place at next year's World Cup finals in Japan and South Korea.

Liberia looked the stronger team from the outset on Saturday but neither side managed to score before halftime, despite having several chances.

Weah then came off the bench 10 minutes into the second half and soon made his mark with a headed goal from a 73rd minute corner.

The former world player of the year had announced he was quitting the international game after losing to Ghana a fortnight ago but back-tracked after Liberian President Charles Taylor intervened.

Liberian officials, including the foreign minister, were prevented from attending Saturday's match by a United Nations travel ban imposed on Liberia for fuelling a decade of civil war in Sierra Leone.

But the atmosphere at the national stadium was friendly and, after the match, several Sierra Leone fans crowded round Weah.

Third-placed Sudan, with nine points, play Ghana away on Sunday before meeting bottom-placed Sierra Leone at home in a fortnight.