The Dutch striker is set to captain his country in Brazil after a below-par season at United that saw them relinquish their Premier League title and fail to qualify for Europe for the first time in over 20 years.
On a personal level, Van Persie struggled with injuries and was limited to 23 starts in all competitions as United endured a disastrous David Moyes era before parting company with the Scot in April after just 10 months in charge.
However, Van Persie feels his limited game time in recent months due to a knee injury could prove a positive for the Netherlands in their World Cup quest.
"I'm feeling good," he told The Guardian.
"Mentally I'm fresh. If you play a full season you can be a little bit tired at the end of the season. But I'm fresh, the knee is fine as well so I'm looking forward to it.
"I'm 100 per cent. It's just that I need a full game now.
"We have three friendlies to play (and) my last game (for United) against Southampton was 67 minutes so hopefully I can play a bit more."
Van Persie became the Netherlands' record goalscorer in October and will be a key player if Louis van Gaal's men are to progress out of a group that includes world champions Spain, Australia and Chile in Brazil.
