The Blues have spent nearly £75m in the past few weeks, including £32m on striker Diego Costa from Atletico Madrid.
Mourinho now believes that he has a squad that can challenge for the title during the new Premier League season.
"The club did a fantastic job by getting the funds to attack these targets. The players that the club sold was unbelievable work and that allowed us to buy players and make the team better and at the same time keep level with Financial Fair Play," Mourinho told the club's official website.
Chelsea get their Premier League campaign underway tonight (Monday) when they travel to Burnley.