LONDON (REUTERS) - A day after Japan's stunning victory over South Africa, normal service resumed in the Rugby World Cup Pool B on Sunday when favoured Samoa proved too strong for the United States in a 25-16 victory.

Samoa had the edge from the start and got the first try when impressive wing Tusi Pisi's grubber kick was touched down by Tim Nanai-Williams, only for an excellent United States break to send Chris Wyles over and cut the islanders' lead to 14-8 at the break.

Captain Ofisa Treviranus stretched it with Samoa's second try early in the second half and four penalties by Pisi and another by Michael Stanley ensured that Chris Baumann's barrelling effort for the Americans came too late to make a difference.

Samoa, who have realistic hopes of making the quarter-finals for the first time since 1995, top the pool alongside Japan with four points to the two of South Africa - who they face next in Birmingham on Saturday.

The US play Scotland next Sunday.