HOUSTON : Japan will never win the World Cup unless football becomes the country's number one sport, midfielder Daichi Kamada warned after their heartbreaking 2-1 defeat to Brazil on Monday.

Asia's best side arrived in North America with ambitions of winning the tournament, and they were touted as outside favourites to go far.

But they were knocked out in the last 32 and have now failed to win a World Cup knockout game in five attempts.

Football has to compete with baseball and a host of other sports in Japan and Kamada thinks that has to change if they want to progress.

"To become a country with serious ambitions of lifting the trophy, you need to have more quality and there are areas where we're still lacking," the Crystal Palace player said.

"We have to keep hyping up Japanese football and making it better, and I feel that if it doesn't get to a level where it's Japan's national sport, we won't be able to win it."

Japan took the lead in the first half against Brazil but conceded an equaliser 11 minutes after the break.

As extra time seemed likely, Gabriel Martinelli struck in the 95th minute to send Brazil through and leave Japan wondering what they have to do to join world football's elite powers.

"It's a shame we lost but if you look at the process leading up to the game and the three and a half years leading up to this World Cup, I don't think there was anything negative or lacking or wrong," said defender Shogo Taniguchi.

"That's how positive and confident I was coming into this."

- 'A little naive' -

Japan breezed through the World Cup's Asian qualifiers and were the first team to book their place at the tournament.

They tuned up by claiming first wins over Brazil and England in friendlies but were then struck by injuries, losing key players Kaoru Mitoma, Takumi Minamino and Wataru Endo ahead of the tournament.

Japan still impressed in North America, drawing with the Netherlands and Sweden and beating Tunisia to finish Group F as runners-up.

Goalkeeper Zion Suzuki said there was room to improve.

"There are still areas where we're a little naive, and I strongly feel that we need to grow," said the 23-year-old, who enhanced his reputation with a series of outstanding displays.

"I don't think it was wrong to approach games against the big teams with the mindset of underdogs and I think if we keep on this path, a great view awaits us at the end."

Japan's next assignment is the Asian Cup, which kicks off in Saudi Arabia in January.

They have won the tournament a record four times but their last title was in 2011.

"The next tournament for us is the Asian Cup, and we will focus on winning that," said Moriyasu, whose future with the team remains unclear after eight years in the job.

"Even if we win the Asian Cup, I don't think it will wash away the pain of losing at the World Cup."