Chelsea responded to disappointment by winning last season's Premier League and Jose Mourinho is wary of a rival doing likewise this term.
Jose Mourinho has again outlined the challenge facing Chelsea as their Premier League rivals aim to bounce back from missing out on the title last season.
Mourinho's men ultimately cantered to glory in the 2014-15 campaign, finishing eight points clear of second-placed Manchester City.
The acquisitions of Cesc Fabregas and Diego Costa paid off handsomely for Chelsea, who wasted little time in strengthening their squad after finishing third the previous year.
And ahead of the new season, the likes of Liverpool, Manchester City and Manchester United have been notably active in the transfer market, while Arsenal's signing of Petr Cech from Chelsea has been hailed as a potentially significant move.
"Two seasons ago we didn't win the title, even before the real start of the transfer window we got immediately Fabregas and Diego Costa - a quick reaction," Mourinho told Sky Sports at the launch of the new Premier League season on Wednesday.
"This year you can see from the reaction of Liverpool, Arsenal, Man City, Man United. They've bought strong, they've bought well.
"They are trying to make an impact because they couldn't get the title."
Chelsea racked up 87 points last term, but Mourinho feels a lower total will be amassed by this season's champions.
"Maybe I am wrong but I have the idea that less points will win the title this season," the Portuguese added.
"Other teams are investing very well and this is not normal.
"Smaller teams are getting some of the best players from some countries. Those players usually only leave their counties for the best clubs but now they go to the promoted teams."