The arrival of the Dutchman could give Kagawa a new lease of life after a frustrating campaign under David Moyes, but the Japan international is concentrating on helping his country out of Group C in Brazil first and foremost.
Kagawa only made 14 starts in the Premier League last season but does not believe there is added pressure on him to impress his new boss in the World Cup.
"I'm not using the World Cup as a place to showcase myself for (Van Gaal)," said the 25-year-old. "I'll deal with that after this tournament is over.
"I think everyone knows I want to do well at the World Cup, and I'm sure everyone else does, too.
"But I don't want to get my priorities mixed up here – the important thing is for Japan to win at the World Cup.
"I know how to get myself into shape. I was able to stay motivated despite the year I had because I had the World Cup to look forward to."
