Chelsea have made a scintillating start to the campaign, unbeaten in all competitions and top of the Premier League.
Mourinho's men have also won their UEFA Champions League group with a game to spare after Tuesday's 5-0 thrashing of Schalke.
The Portuguese was effusive in his praise of his players after that performance in Germany but, speaking ahead of Chelsea's trip to Sunderland on Saturday, the Portuguese warned against any drop in standards.
"Every player in my squad is fantastic and I'm so happy with all of them," Mourinho said. "The only risk we have is complacency.
"I have enough experience not to be over the moon when we win or in hell when we lose. We've improved where we can without worrying about other factors and other teams.
"For us every competition is important so we don't rest players and we try to play with our best team."
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