By FOX Sports staff
Kagawa had an injury-interrupted first campaign at Old Trafford last term following a big-money move from Borussia Dortmund but still managed to net six goals in 26 appearances, including a clinical hat-trick against Norwich back in March that was a real display of his quality.
But since Moyes took over from Sir Alex Ferguson in the summer, Kagawa has failed to feature for United apart from a seven-minute substitute appearance in the Community Shield against Championship side Wigan.
However, the 24-year-old remains a key player for Japan and, after another impressive showing in the Samurai Blue's 3-1 friendly win over Ghana on Tuesday, expressed his frustration at being constantly ignored by his new club manager.
"Please ask David Moyes why I'm not in the side," he told reporters, according to ITV.
"It is frustrating [to be] not playing but to score a goal like that [against Ghana] gives me confidence. Hopefully I can take that back to my club 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. I missed one in the first half tonight [Tuesday] so when the chance opened up in the second for me to shoot, I wanted to take it on."
Despite his relative youth, Kagawa has already enjoyed plenty of success having won two Bundesliga titles and a DFB-Pokal with Dortmund, before winning the league with United last season.