Japan forward Yuki Otsu scored in the first half in a 1-0 win over 10-man Spain in men's Olympic soccer, hurting the Spaniards' chances of winning a gold medal.

The Spanish team recently won its second consecutive European Championship, to add to the 2010 World Cup won in South Africa. Spain also holds the European under 19 and under 21 titles.

The European champions enjoyed more of the ball throughout the 90 minutes but they struggled to deal with the pace of Japan's attacks, with David De Gea, Manchester United's young goalkeeper.

“It was an important win for us,” Captain Maya Yoshida said. “Spain are a very strong team in the group and we played well against them. We worked really hard and we will enjoy our victory. We can get a lot of confidence from this.”

Spain, hyped as one of the favorites to win a gold medal, will now look to the national side's experience at the 2010 World Cup for inspiration. Spain lost its first group stage match in South Africa to Switzerland, but went on to win the tournament.

The Olympic side has two more matches to turn it around, against Group D opponents Honduras and Morocco.

“Our aim is to win both of them. We have to,” forward Juan Mata said. “We need to improve some things and we have to play better.”

However, Brazil got their Olympics started with a 3-2 win over Egypt in Cardiff, whilst Team GB, playing their first Olympic football tournament since 1960, began with a 1-1 draw with Senegal.