Ahead of Monday's opening game away to newly promoted Burnley, he refused to say whether long-serving Czech Republic international Petr Cech would remain his number one goalkeeper or whether Belgian Thibaut Courtois, who has returned to the club after three seasons on loan at Atletico Madrid, would replace him.
"Chelsea has two of the three best in the world and this is something unique," Mourinho said.
He believes that the ability to rotate them if necessary without sacrificing any defensive solidity, plus the acquisition of players like Brazilian Filipe Luis and Spanish internationals Cesc Fabregas and Diego Costa, as well as the return of striker Didier Drogba, will make the London side stronger than last season when they finished third.
"Last season we were not feeling as though we were a title contender but in fact we finished very close to the title," Mourinho said.
"We didn't feel as one of the favourites for the Champions League and we played a semi-final, so we did well.
"This season obviously we bought some key players, we believe and we are feeling that the new players have brought the squad and team into another dimension.
"I have to respect the opponents and efforts the other teams made to improve their already top teams, but we all feel we are title contenders."
Mourinho, who returned to Stamford Bridge after leaving Real Madrid in 2013, has a remarkable record in his second season with previous clubs, winning the championship each time with Porto (2004), Chelsea (2006), Inter Milan (2010) and Real Madrid (2012).
Porto and Inter also won the Champions League the same season.