GLASGOW, Scotland (AP) -- At the Olympics, Spain's European and world soccer titles aren't much help.
The Spanish men, considered to be one of the medal favorites, lost to Japan 1-0 Thursday in their opening match at the London Games.
Spain's Olympic team, which is mainly for players under 23, 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," said Spain forward Juan Mata, who plays for Chelsea and is one of the three overage players. "We need to improve some things and we have to play better."
Japan forward Yuki Otsu scored the only goal at Hampden Park, breaking away from his marker during a corner kick and tapping a shot past goalkeeper David de Gea in the 34th minute.
Spain finished the match with 10 men after center back Inigo Martinez was sent off while trying to stop Japan forward Kensuke Nagai.
"It was an important win for us," Japan 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's senior team won its second straight European Championship this month, and won its first World Cup four years ago in Johannesburg. Mata scored in the Euro 2012 final in Kiev, Ukraine, a few weeks ago.
Spain started well in Thursday's match but couldn't break through a solid Japan defense and didn't have a meaningful shot on goal.
Spain's youngsters mimicked the slick passing game the national team does so well, pressuring Japan but failing to test the goalkeeper with any dangerous shots. Japan's defenders were also able to strip the ball off Spain's attackers several times in the penalty area as they threatened to shoot.
Martinez's red card in the 41st minute made things tougher.
"With one player less, we were looking for an equalizer," Spain coach Luis Milla said, "which isn't our style."