Striker Madjer scored six goals on Saturday to lead Portugal to a 10-3 demolition of Cameroon in FIFA's Beach Soccer World Cup. Argentina beat Bahrain 2-1 to reach the competition's quarter-finals.
Madjer became the tournament's leading scorer, having scored twice in Thursday's 5-4 win over Uruguay, and the result moved Portugal -- last year's runner-up to France -- to the top of Group C with six points from two matches.
Uruguay, which defeated the Solomon Islands 10-5, was second with three points.
Argentina beat Bahrain in Group D with goals by Ezequiel Hilaire and Santiago Hilaire, securing a spot in the quarter-finals.
The Argentinians have six points, three more than Bahrain and Nigeria, which eliminated Italy with a 4-3 victory.
Yesterday, defending champion France -- a 7-4 winner against Spain in its opener -- were to play Canada in Group B, while host Brazil -- a 9-2 winner over Poland in Group A -- were to face Japan.
Brazil was held to a disappointing third-place finish in the inaugural FIFA tournament last year.
This year's tournament has 16 teams, four more than last year. Two nations from each group advance to the quarter-finals.