GLASGOW, SCOTLAND - JULY 26: Kensuke Nagai of Japan competes Oriol Romeu of Spain during the Men's Football first round Group D Match of the London 2012 Olympic Games between Spain and Japan at Hampden Park on July 26, 2012 in Glasgow, Scotland. (Photo by Stanley Chou/Getty Images)

Glasgow, Scotland – Japan produced a major shock in men's Olympic football on Thursday, beating medal favourites Spain 1-0.

Japan forward Yuki Otsu broke away from his marker during a corner in the 34th minute and the ball landed right at his feet for a simple tap-in past Manchester United goalkeeper David De Gea.

Spain started the match brightly with good build-up play and quick passing in the first 20 minutes, but they couldn't break through a solid Japan defense and didn't have a meaningful shot on goal.

It wasn't only Japan's back line that was troubling the Spaniards. Japan forward Kensuke Nagai caused major problems for them throughout the match, slipping behind defenders with quick runs. Spain center back Inigo Martinez was sent off for a foul while trying to stop Nagai from scoring.

Japan took advantage of the extra man in the second half and the match could have been a rout had the finishing been more accurate. Nagai continued to trouble the defense, shaving the post in the 58th minute.

Spain's under-23 team wants to win Olympic gold to add to the World Cup and European Championship titles held by the country's full national team. The loss is a huge blow for Spain, touted as one of the favorites to win the tournament, but not insurmountable.

Spain's national team lost its first group stage match to Switzerland at the 2010 World Cup and then went on to win the tournament.

Spain's youngsters mimicked the slick passing game the national team is so well known for, 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.

Japan has been a rising steadily in world football, qualifying for the 2010 World Cup and building a strong youth program. The victory against Spain rates among Japan's greatest.

But coach Takashi Sekizuka was modest when asked if this was the case.

“We looked forward to this match very much, and showing how much we have was the main point,” he said. “We are very pleased with the result.” – Sapa-AP