Hyperbole abounded after Thursday's upset, reminding people that Japan's men can play a bit too after the country's women sensationally won last year's World Cup.
Japan's Nikkan Sports daily described the win as the "Miracle of Glasgow" after Yuki Otsu's first-half goal proved the difference in the Group D game.
Despite being an under-23 competition, Spain, world and European champions at senior level, are regarded as potential gold medallists at the London Olympics.
Japan's job was helped by the sending off of midfielder Inigo Martinez just before half-time.
"I was sobbing at the end of the game," match-winner Otsu told Japanese media after his close-range goal helped Japan beat Spain for the first time at any level.
"We are here to win the gold medal," added the German-based midfielder, who was tweeting "Please! Please!" from the bench in the second half after being withdrawn with a bruised ankle.
"Japan shock the world!" screamed the Sankei Sports, while the Mainichi Daily's headline ran "Otsu sinks unbeatable Armada" and the win was a hot topic on Friday's television talk shows.
The government also praised the result, Chief Cabinet Secretary Osamu Fujimura called it a "truly a great start to beat mighty Spain."
Japan's men last won an Olympic medal at the 1968 Mexico Olympics when they took bronze but have not advanced beyond the group stages since the 2000 Sydney Games.
A Japan team full of fresh-faced players such as Hidetoshi Nakata and Yoshikatsu Kawaguchi famously stunned Brazil 1-0 at the 1996 Atlanta Games, dubbed the "Miracle of Miami."
The Japanese players, however, insisted after beating Spain that there was nothing miraculous about the win.
"It's not a miracle," said Otsu. "It's the result of hard work and preparation."
After Japan's world champion women won their opening game, the pressure had been on the men, who caused a stir by flying to London in business class while the women sat in premium economy.
Japan's world champion women came to symbolise the determination of a nation united in recovering from last year's deadly tsunami and resulting nuclear crisis.
"It's a good job we won," said Japan captain Maya Yoshida. "If we had lost after they won, you know what people would have been saying about us."
