The Blues followed up the pre-World Cup signing of Cesc Fabregas with the captures of Diego Costa and Filipe Luis from Atletico Madrid. Promising midfielder Mario Pasalic has also joined from Hajduk Split.
"I have to say my club did a fantastic job, and not just because of what we bought, but because we did it in almost record time. The transfer market closes 31 August and we close our market on July 19. We finished the market today," said Mourinho.
"The club did fantastic, we knew the targets, we knew the players and the club attacked them and their clubs at a very early stage.
"We got exactly what we need and what we want. The squad is one which I like very much and I look forward to starting the season."
Mourinho believes he has a squad capable of winning the Premier League next season, but accepts that any of the title hopefuls could also easily end up fifth, with Manchester United expected to challenge again under Louis van Gaal.
"Last year, if you had asked me in July, I would never have said Man United would be outside the top four. This season I will tell you one (to miss out) and I have a big percentage of making a mistake," said Mourinho.
"There were good teams last season and there will be better teams this season because everyone is investing.