• Spain 0-1 Japan
• Read Paul Doyle's minute-by-minute report
The vast majority in a healthy Hampden Park attendance of 37,726 turned up with the expectancy of being dazzled by the reigning world and European champions. They left having witnessed something else; a terrific Japanese performance which left Spain in the rare position of having received a bloody nose. But for wastefulness from Japan – which at times had to be seen to be believed – the margin of their victory could genuinely have embarrassed the Spanish.
It is difficult to quantify the magnitude or otherwise of an Olympic opening group game but Japan still defeated a team which included David de Gea, Jordi Alba and Juan Mata from the start. Those players, and the remainder of this Spanish squad, will carry the heavy burden of succeeding a side who have made international history in major tournaments.
In Spain's defence, they played the entire second half with 10 men. Iñigo Martínez tugged Kensuke Nagai sufficiently to knock the Japan forward to the ground as he bore down on goal three minutes before the interval. By that stage, Spain were already a goal down.
"With one player less, we were forced to chase the game," said Luis Milla, Spain's coach. "That isn't the style of the Spanish team." So there you have it – perhaps the best way to beat the all-conquering Spanish team is to somehow trigger a bout of indiscipline. Getting a goal in front before such a scenario occurs, of course, may be the tricky part.
Milla conceded there is added heat on his squad, given the recent Spanish defence of the European Championships. "We already knew about this extra pressure to win a gold medal, coming into the games," the coach said. "Everyone at the Spanish FA is delighted to have this pressure."There may be more to come. If Spain fail to win Group D, there is the very real prospect of them meeting Brazil at the quarter-final stage.
Yuki Otsu may have proved Japan's scoring hero but their stars featured elsewhere. Nagai was a constant menace to the Spanish defence while, in midfield, Hiroshi Kiyotake excelled.
"This is still only the first match," cautioned the Japan coach, Takashi Sekizuka. "There are still many games to play. We look forward to playing alongside Spain again in the knock-out round."
Spain's failure to defend a perfectly routine corner from Takahiro Ogihara prompted their demise. Under a weak challenge by the Barcelona full-back Martin Montoya, Otsu calmly slotted home.
The aberration from Martínez followed, it would have a key influence on the second half where Japan probably could not believe how many chances they created and squandered.
De Gea saved acrobatically from Keigo Higashi before Nagai screwed a shot wide in the culmination of a wonderful sweeping move also involving Hotaru Yamaguchi and Higashi.Kiyotake should have had the goal his overall play merited but could not hit the target at the end of a burst from midfield. The Manchester United goalkeeper spread himself to save from Nagai and Yamaguchi shanked an attempt well wide, both in the game's dying stages.
Spain had offered next to nothing by way of a response. Milla's team were sluggish and lacking in invention. "We will treat the last two [group] games like cup finals," the coach insisted. Thankfully for Milla, the Spanish are have proved rather good at them.