Holtby moved to Spurs last month from Schalke.
“This club are evolving every year, maybe even every month,” said Holtby. “It’s not as though this has come from nowhere because the club have been in the top four or five for the last three years. I’ve made a really big decision in my career but it’s the right one.
“We’re in fourth place at the moment and that’s where we’re aiming to go. The squad, the club are getting bigger all the time and we deserve to go into the Champions League. It’s a hard route but I think we have everything to get there.
“The quality here is fantastic, even among the players who weren’t in the squad for the Newcastle game. The level of the team spirit is very high and that’s why we are able to win tight games like that one.”