Spain's 2012 Olympic Games began in a surprising fashion as they were defeated 1-0 by Japan in their opening game this afternoon.

Spain entered the tournament as one of the favourites after their full team became the first side to win three consecutive major international tournaments this summer.

However, Yuki Otsu's first-half goal was enough to give Japan the shock victory that sends them to the top of Group D, while Spain find themselves propping the other three teams up at the bottom.

Here, Sports Mole dissects one of the biggest shocks in Olympic football history.

Sports Mole's analysis:

Spain's statistics:
Shots 6
On target 3
Possession 65%
Corners 6
Fouls 11

Japan's statistics:
Shots 12
On target 5
Possession 35%
Corners 4
Fouls 17

Was the result fair?
Yes, and the fact that it was is perhaps the most impressive thing of all. Spain started well but Japan always looked dangerous and had more clear-cut chances than their opponents.

Spain's performance
A far cry from the high standards we expect from any Spain team, regardless of their age. Looked assured in possession at the start but struggled with the work rate and pace of Japan, particularly when they were reduced to 10 men.

Japan's performance
Sensational. Didn't let Spain settle into their preferred rhythm for a prolonged period of time and never thought of parking the bus in front of the goal, even when leading by just one goal in second half injury time.

Sports Mole's man of the match
Goalscorer Yuki Otsu grabs this accolade. The striker never let the Spanish defence rest and deserved to get the goal that completed his side's famous victory.

Referee's performance
Decent performance from the ref with no big mistakes. Perhaps a bit niggly at times but got the big decision - Martinez's sending-off - spot on.

Biggest gaffe of the game
Martinez's tackle was a silly one to go for, especially with your team trailing. Brought down the striker as the last man and the ref had no option to send him off. Who knows what could have happened if Spain had kept all 11 men on the field?

What next?

Spain: Honduras are up next for Spain and, while they will still be expecting a convincing win from that game, they'll no doubt be taking it even more seriously than they may have otherwise.

Japan: Japan now top the group and will face Morocco in their next match, where they could secure qualification.