The 23-year-old has found himself on the fringes of Andre Villas-Boas' star-studded squad this season.
But he gave a useful reminder of his worth on Tuesday with a hand in three of Spurs' four goals against Aston Villa.
Holtby said: "I know Tottenham are going to do something big and I know they are going to have a really good, strong squad. I want to be part of that.
"I knew when I came to Tottenham it was going to be very tough and a hard challenge.
"I wanted this challenge. I could have stayed at Schalke, I could have played there all the time.
"But I wanted this test and to fulfil my dream of playing in the Premier League for a top, top club."