Gerald Sibon kept the Netherlands in the Olympic football tournament yesterday by converting a second-half penalty kick in his team's 1-0 win over Japan, and Nigeria, Cameroon, Belgium and Ivory Coast also found ways to reach the quarter-finals.

Nigeria defeated the United States 2-1, Belgium beat New Zealand 1-0, Ivory Coast edged Australia 1-0 and Cameroon held Italy to a 0-0 draw. Italy, Brazil and Argentina had already advanced before yesterday's matches. The Brazilians routed China 3-0, while Argentina got past Serbia 2-0.

The Netherlands, a pre-tournament favorite, was in danger of being eliminated from the competition until Liverpool striker Ryan Babel was fouled inside the area in the 74th minute to bring the spot kick.

Sibon, who had already scored a crucial equaliser late in the game against the United States three days earlier, hit a low shot down the middle of the net as goalkeeper Shusaku Nishikawa dived to his right.

The win gave the Dutch five points, enough for second place in Group B after Nigeria's win over the US in Beijing. The Netherlands will face defending champion Argentina in the second round.

Nigeria finished with seven points, two more than the Netherlands and three in front of the United States. Winless Japan had zero points. Nigeria will now play Ivory Coast, which edged Australia due to an 81st-minute goal by Salomon Kalou.

Argentina, trying to become the first team to win consecutive Olympic titles since Hungary in 1964 and '68, finished the group stage perfect by beating Serbia in Beijing with goals from Ezequiel Lavezzi in the 13th and Diego Buonanotte in the 81st.

Argentina finished Group A with nine points, three more than Ivory Coast. Australia and Serbia ended with one point each.

Brazil, seeking their first gold medal in football, eliminated host China in Qinhuangdao with a pair of goals by Thiago Neves and another by Diego. The Brazilians also finished group play with three wins and nine points. The five-time world champions will play Cameroon in a rematch of the 2000 Olympic quarter-final in Sydney, when the Africans came out victorious.

Belgium was second in Group C with six points after defeating New Zealand in Shanghai on a 35th-minute winner by Faris Haroun. Belgium will play Italy in the quarter-finals.

Italy finished with seven points in Group D, while Cameroon advanced as runner-up with five points.