After the United States and seven European teams reached the quarterfinals of the Women’s World Cup four years ago, it was widely assumed that soccer’s global power base would remain stalled like a weather front in those regions four years later.

But this is a tournament of surprise, upended expectation and cracks in the foundation of women’s soccer tradition. The United States and Germany, ranked Nos. 1 and 2 in the world, with six world championships between them, were sent home early and stunned.

Five European teams remain, but it is Japan that might be the most impressive contender, a sagging power suddenly revived and the only team left standing to have won a World Cup.

With unity of movement, a mostly unsolvable defense and tactical flexibility, Nadeshiko, as the team is known, has delivered 14 goals and conceded only one in four matches ahead of Friday’s meeting with Sweden in the quarterfinals in Auckland, New Zealand. Hinata Miyazawa has been a revelation at midfield, scoring five goals in this World Cup — the most of any player — after scoring only four times in 22 previous appearances.

Having wilted after winning the 2011 World Cup in a penalty kick shootout against the United States, Japan has bloomed anew with versatility to play the possession style of short passes known as tiki-taka or to launch searing counterattacks. After a blistering 4-0 loss to Japan during group play, Spain Coach Jorge Vilda said that his team’s defeat had been psychic as well as numerical. “Mentally, of course,” Vilda said, “this has done some damage.”

After Japan defeated Norway by 3-1 in the round of 16, Caroline Graham Hansen, the Norwegian star who plays for the Champions League winner Barcelona, said that Japan showed why it might be the best team in the tournament.

“They’re so disciplined and very structured in the way they play offense and defense,” Hansen said.

Friday’s quarterfinal might play out as an engaging challenge of physicality versus technique. Sweden has scored four of its nine goals on corner kicks, a total that nearly grew last Sunday as it packed the six-yard box against the United States like a crowded elevator.

But the Swedes could not manage a goal in 90 minutes of regulation and 30 minutes of overtime before subduing the Americans, finally and microscopically, on penalty kicks. Only the brilliant anticipation and reaction of goalkeeper Zecira Musovic kept the outcome from being reversed. A number of Sweden’s players appeared near exhaustion, particularly left back Jonna Andersson, who was beaten down the flank repeatedly by the speed of Trinity Rodman and Lynn Williams.

Not until kickoff on Friday will it become evident whether Andersson and her teammates have had sufficient time to recover to face a relentless Japanese team that has been much more incisive in each of its matches than the United States was in any of its games.

“They don’t play as directly as the U.S., so it’s going to be a different kind of game,” said Sweden’s coach, Peter Gerhardsson. “It’ll be more about possession.”

Sweden may set its defense low, trying to absorb and dissipate Japan’s attack; its goal, Gerhardsson said, is normally to try to win the ball back after its opponent makes four or five passes.

“With Japan, maybe it’s 10 to 15 passes, but we still want to win the ball,” he said. “And, then, transition is going to be important.”

Japan entered this World Cup ranked 11th by FIFA, a sign of how far its fortunes had slid after winning the World Cup and returning to the final in 2015. Its inspiring 2011 victory came four months after an earthquake and tsunami had devastated the country’s northeast coast, killing more than 15,000 people and displacing thousands more.

Even in defeat that year, the American forward Megan Rapinoe said recently, she considered Japan’s victory “one of the greatest stories in all of sports.”

But that success began to ebb. When the Japanese team traveled to the 2012 London Olympics, it had to fly coach, while its men’s team, mostly under-23 players, flew business class on the same jet. The women won a silver medal, while the men finished fourth.

In the final of the 2015 World Cup, Japan was routed, 5-2, by the United States, largely on the predatory audacity of Carli Lloyd, who scored three goals in the first 16 minutes, including a shot launched from midfield. When Japan failed to qualify for the 2016 Rio de Janeiro Olympics the following summer, a makeover began, with the aim of overhauling the senior team but also of increasing the participation of female soccer coaches, referees and players, to create a larger talent pool from which to draw. The stated goal was to register 300,000 female players — up from 50,500 at the time — by 2030.

Japan also hired the first female coach for its women’s national team: Asako Takakura, who had been a pioneering player. In an interview with The New York Times months before the 2019 World Cup, she predicted that Japan would win the tournament. She wanted her players to express their individualism, she said, instead of simply prizing the collectivity of the group, which had been a tradition on some previous teams.

Instead of lifting the trophy, though, Japan scored only three goals in four matches and exited quickly and meekly. Two years later, Japan’s gold-medal dream at the 2021 Tokyo Olympics ended when it was eliminated by Sweden in the quarterfinals. Takakura was replaced by Futoshi Ikeda, who coached Japan to the 2018 under-20 Women’s World Cup title.

As the current World Cup began, many remained skeptical about Japan’s chances, including Takakura, who told Agence France-Presse that Japan was “left behind by the sudden strides that the rest of the world were making” in terms of resources poured into women’s soccer. Not until 2021, for instance, did Japan’s women’s league become fully professional.

Shinobu Ohno, who was a member of the 2011 championship team, told the French news agency that Japan’s national team had become sclerotic, unable to adapt to teams that were physically stronger and more tactically adept. But pretournament doubt has since been replaced by ascendant optimism.

Ikeda has constructed a team built on agility, mobility, cohesion and a liberating joyfulness. Nine of Japan’s 23 players are attached to clubs in top women’s leagues in the United States, England, Italy and Sweden, and that has helped develop the confidence, fearlessness and tactical versatility evident in the World Cup.

“We’re ready to fight against anyone,” said Saki Kumagai, Japan’s captain and the only player remaining on the roster from the 2011 World Cup.