Shinji Kagawa has told reporters to "ask David Moyes" why he isn't getting playing time for Manchester United.
Kagawa was one of Sir Alex Ferguson's last additions, signing for the Old Trafford club last summer from Borussia Dortmund.
An injury hit campaign saw his playing time limited but several impressive performances, including a hat-trick against Norwich, gave Manchester United a glimpse of his potential.
However, the Japanese international has played just seven minutes of football this season, coming off the bench in the Community Shield tie against Wigan Athletic last month.
Questions have asked why Kagawa is not featuring. He wasn't even named as a substitute in the 1-0 loss to Liverpool, inspiring Dortmund fans to start a #FreeShinji campaign on Twitter.
Kagawa gave Moyes a reminder of his talent in Tuesday's 3-1 win against Ghana by scoring a fine goal for Japan. After the match he admitted he has been left frustrated by his bit-part role at Old Trafford.
He told AFP news agency: "Please ask David Moyes why I'm not in the side.
"It is frustrating not playing but to score a goal like that gives me confidence. Hopefully I can take that back to my club with me and things will improve.
"It's hard not playing regularly. Some days the frustration is worse than others; it comes in waves.
"So it's nice to come back to Japan and get to play, and to score felt good.
Although revealing his frustration at Moyes, he did reveal that he is happy to bide his time and wait for his opportunities to impress for the Premier League champions.
"I just have to keep working hard and keep pushing for my chance. When I get back it will be a challenge to get into the team.
"When I get back to my club I have to wait for my chance in the Champions League and the Premier League. I'm sure my chance will come."