It is a technique called 'mind-setting' which he discovered while battling two career-threatening knee injuries.
Vlaar, a £3.2million summer buy from Feyenoord, said: "I'm a real believer in mind-setting. It's a technique in which you 'play' little bits of games before you even step on to the pitch.
"You recognise certain situations you will have to deal with during a game and you play them out in your mind.
"It worked great for me at Feyernoord last year. We had a difficult start to the season but it became a great one as we finished second and I achieved my goal of playing for the Netherlands in the Euros, which was amazing.
"A personal trainer in Holland introduced me to the technique. Every minute of every training session you have to succeed, you have to get better. You have to have the will to succeed.
"You also have to visualise doing the right things during games. So at 5.30 when we kick-off against Manchester United, I'll already have won some headers against Van Persie and some tackles against Rooney!"