The Japanese star joined United from Bundesliga side Borussia Dortmund last summer.
The 24-year-old made his first league start under David Moyes against West Brom on Saturday.
“I have to take this like some kind of message (from the manager),” he said.
“I need to improve more and more, or I cannot survive at this club.
“I have to take this in a positive way and keep trying to do my best.”
What is your opinion? Feel free to discuss the article under. You have to comment by using your Facebook profile. Be fair and have respect for other people and opinions!
The reputation of the Premier League means it is the most popular and one of the most watched leagues in the world.
Five English clubs will compete in the last sixteen of the Champions League for the first time ever as Liverpool, Manchester United, Manchester City, Chelsea and Tottenham face some difficult away matches.