De Bruyne, who spent last season on loan at Bundesliga side Werder Bremen, capped his Premier League debut with a Man of the Match display in his side's 2-0 win over Hull City.
The 22-year old faces stiff competition for places in midfield, but he says that Mourinho's trust has given him a real boost as his faces his first full season in England.
"It's always nice when the manager has confidence in you; I never have any stress before a match," he told Chelsea's official website.
"Football, for me, is still a game, there's a lot of pressure but that doesn't matter.
"You just have to try your best; sometimes you play good and sometimes you are a bit nervous, but that's football."
De Bruyne also recognised how much of a task he has on his hands to keep hold of his place in the first team, something he says will spur him on.
"We know we have six good players for that position so we have to prove ourselves on the field," he said.
"The manager will probably rotate so we will see what happens. I've started well and team rotation is normal when you play so many games.
"If you play for a club like Chelsea you have more players at a high level, you have to fight for your spot which is good for the team."