In an interview with Chelsea's members' magazine published on Monday, the outspoken Portuguese coach also said winning a second title would be tougher.
"It will be harder because other teams understand how strong we are and they have to improve. If they are the same, they know they have no chance."
Chelsea, who won their first championship for 50 years, finished the season 12 points clear of nearest rivals Arsenal and 18 ahead of third-placed Manchester United.
Asked if his side were still hungry for trophies, Mourinho said his plans for bringing in new blood were partly designed to counter complacency.
"In reality you could say I don't need another midfielder. I have enough. If you don't need it from a football point of view, you need it from a mental point of view.
"A player cannot think that because I was good I have my place and because I have my place I don't need to have the same commitment.
CLUB SUCCESS
"For a manager it is difficult, especially after success...You can't be emotional, you have to think of the most important thing and you have to think about the club."
Chelsea were close to signing Liverpool captain Steven Gerrard last week but at the last minute the England midfielder opted to stay with Rafael Benitez's European champions.
The London club has been linked in the media with a raft of high profile players, largely because of the spending power of Russian billionaire owner Roman Abramovich.
Mourinho, who returned to Stamford Bridge last week from holiday, has sold midfielder Scott Parker and strikers Mateja Kezman and Mikael Forssell, while Argentine striker Hernan Crespo is back from a year's loan at AC Milan.
His only significant buy so far has been Spanish left back Asier del Horno from Athletic Bilbao and he is still in the market for a midfielder and a striker.
Arsenal manager Arsene Wenger complained on Sunday that Chelsea's wealth had distorted the transfer market. "There is a price for Chelsea and there is a price for everybody else. You have to wait for them. It's frustrating..." he said.
Mourinho told the magazine he had no problem with personal motivation, after winning the title and League Cup but missing out on the FA Cup and Champions League.
"I'm frustrated because I did not win everything," he said.
