Andre Villas-Boas' side beat Newcastle at White Hart Lane on Saturday to strengthen their grip on fourth place and the final qualification spot for Europe's premier competition.
Holtby is Spurs' latest signing, having joined for £1.5 million from Schalke in January, but says momentum has been growing at the club long prior to his arrival.
|4/5||Tottenham are 4/5 with BetVictor to finish in the top four
"This club has been in the top four or five for the last couple of years, so I've made a really big decision in my career and it's the right decision.
"Our aim is to go to the Champions League. The club is getting bigger all the time and we deserve to be there.
"It's a long way and a very hard route we are on but with this squad, and the whole background with the staff, I think we're able to play in the Champions League. It's a fantastic club to come to.
"The team spirit is very high, that's why we win these tight games. It's fantastic to be here and the reception of the fans is always perfect."
Holtby lauded Gareth Bale after the Welshman delivered another match-winning performance to seal three points against Newcastle but was keen to emphasise the efforts of the team as a whole.
"He [Bale] is a world-class player, one of the best in the world I think," he enthused. "What he's producing every week is fantastic, but you have to give the credit to the others – we're a team with 11 men.
"Of course Gareth scores goals and he is perfect for us, but every player in the team works hard for the club.
"You see at the end how Hugo [Lloris] saved that chance, and the defenders put their bodies into every shot. Everyone is working really hard and that's the key of the game, playing football with 11 or 14 men, who are strong.
"To have a player like Bale makes the difference and to play with him is a great feeling, but it's not just him."