Japan’s shock Asian Cup quarter-final exit has left their big-money players dumbfounded and plunged the future of Mexican coach Javier Aguirre into doubt.

The holders crashed out on penalties against the United Arab Emirates after superstars Keisuke Honda and Shinji Kagawa missed from the spot in Friday’s nail-biter in Sydney as Aguirre paid the price for not rotating his squad in the group stages.

Kagawa, who has gone horribly off the boil for Japan since losing his place at Manchester United last season and returning to Borussia Dortmund, was inconsolable after slamming his kick against the post, allowing the UAE to win the shootout 5-4.

“I missed and we lost — I’m deeply sorry,” said the playmaker, who wasted several good opportunities to win the game, which finished 1-1 after extra time, and whose prolonged spell in the doldrums has been a source of concern for his Japan team-mates.

“I can’t turn back time,” he shrugged. “Maybe there’s a reason why I missed.”

Honda, who had scored twice from the spot in the group stages, struggled to find an explanation.

“It’s a harsh reality,” said Japan’s blond cult hero, who blazed the team’s first penalty wildly over the bar. “It shows we were perhaps a bit naive in not being able to cope with the pressure to win the tournament.

“I said it after the World Cup too but we weren’t prepared for such a tough game,” added the AC Milan midfielder, comparing the team’s early exit to last year’s flop in Brazil. “Mentally we were not able to adjust.”

Asked about his woeful spot kick, Honda replied: “I’ve seen big players miss penalties on TV and it hurts that I’ll be remembered for it now too. I tried to hit it hard but I just didn’t catch it right.”

The Japan Football Association (JFA) now have a big decision to make over Aguirre, who is scheduled to appear in court in Valencia next month following an investigation into match-fixing dating back to his time as manager of Zaragoza in 2011.

The 56-year-old took over after the World Cup for a record salary for a Japan coach of an estimated $2.45 million a year, but failure in Australia could lead to a mutual parting of ways as the JFA look to the 2018 World Cup qualifiers which begin in March.

Who Japan turn to in the event that Aguirre’s contract is paid out remains to be seen. But irrespective of the outcome of the match-fixing probe by Spanish prosecutors, the lack of tactical acumen shown by the Mexican was alarming.

Inter Milan will be upset that defender Yuto Nagatomo suffered a hamstring injury at the tournament, and that he was forced to soldier on through extra time against the UAE with Aguirre out of substitutions.

“It’s hard to take,” said Nagatomo. “I was a burden to my team. We lost at the World Cup and have gone out at the Asian Cup. We have to accept it. Mentally we all have to be stronger.”