Celtic-bound Shin Yamada insisted he's only concentrating on playing for Japan after making his international debut as he closes in on a £1.5 million move to Parkhead.
But he hit out at his own displays this season and admitted he was disappointed with his performances in his homeland.
Celtic seem set to make Yamada their latest signing from Japan, with the 25-year-old Kawasaki Frontale striker ready to travel to Glasgow after he plays in the EAFF E-1 Football Championship for his country, with the final game against South Korea next week.
He made his international bow after coming off the bench in Japan's 6-1 win over Hong Kong in a match watched by just 687 fans in Yongin, South Korea.
And while he admitted he was proud of making his debut in a Japan squad based of domestic players only, he admitted he was disappointed in his return of just two goals in 21 games this season compared with 19 last term.
He said: "I went into the game with the feeling that this was my chance to impress and although we won, I thought I could have done more.
"I think that going forward, when we compete in the World Cup, it will be against far more difficult opponents, so I need to keep that in mind as I work on my national team progress.
"I thought I might have been able to score a goal, but I think I learned a lot from this.
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"On a personal note, I have to admit I have had a disappointing season. I set high standards for myself and I don't think I met them if I am being honest.
"Yes, I enjoyed a very good season previously and scored a lot of goals, but for whatever reason it didn't happen again this season.
"I think the team played in a different style and that made a difference, but I am fully aware I have to raise my standards."
