United saw off Swansea City on Saturday, three goals in the final 10 minutes completing a second successive rout.
United saw off Swansea City on Saturday, three goals in the final 10 minutes completing a second successive rout after they hammered West Ham United in their opening game of the season.
Mourinho feels the biggest difference in his team from a year ago, when he had just taken charge, is in their mentality, although he warned his players they are yet to be tested.
"The word that better describes the team now is 'confident'," said Mourinho, whose side won in South Wales with goals from Eric Bailly, Romelu Lukaku, Paul Pogba and Anthony Martial.
"The team starts the game confident, the team starts the second half confident.
"The thing that I want to see -- but I don't want to see -- is the team losing and see the way they emotionally react to it, because that's another change -- losing and trying to change the result.
"Because in this moment everything is going in our favour. But it's not always a motorway. You always find difficult roads and roadworks and we have to be ready.
"We started last season with two matches and six points and we finished sixth.
"It's not a lesson, it's a reality of football -- two matches are not the end of the world for people that lose and it's not paradise for people that win.
"I am happy, of course, and the quality of the performance gives me even more confidence."
Mourinho praised his side for keeping their feet on the gas in the second half and paid tribute to his substitutes after Martial came off the bench to score for the second game running.
"In both matches, winning 1-0 at half-time, we didn't start the second half looking like we had to keep a clean sheet to win the match," said Mourinho.
"We always looked like, 'Let's at least control the game by having the ball and trying to score more goals.' And we did that in both matches.
"Then players on the bench have great quality, so it is easy for me to make changes, and good players make managers look even better."
Mourinho dismissed suggestions that Pogba, who scored United's third goal, could have been sent off before half-time when he fouled Martin Olsson moments after being booked for catching Tom Carroll.
"I don't even think that the first yellow card was so deserved," he said.
"The yellow card is a little bit out of context because I thought that Jonathan (Moss, the referee) was having a certain kind of criteria that didn't bring easy yellow cards.
"Because there were actions, especially one on (Nemanja) Matic, that was a yellow card and he decided to speak with the players and go in that direction. So I thought with Paul he would do the same."
Swansea unravelled in the closing stages of their first game since selling key man Gylfi Sigurdsson to Everton.
But head coach Paul Clement said: "We were competitive for long periods of the game –- right up until the second goal.
"The difference between the sides for a long time was a set-play. Although we had to defend more than they did, I thought our shape was good and we didn't let them have any real clear-cut chances.
"There were enough good things in the first half for me to say at half-time that we were still very much in the game and must not let our confidence get affected."