Marcus Rashford and Marouane Fellaini came off the bench to score in the 2-0 win over Leicester which maintained their 100 per cent start to the Premier League campaign.
United are top of the table after scoring 10 goals and conceding none in their opening three matches.
The Red Devils kicked off the 2016-17 season with three wins in a row but Mourinho believes he has more quality at this disposal this time around.
“I think we played very well,” he told BT Sport.
“There is a difference in the quality of our football. We have played better.
“The team is playing very well, very confident, great football. I like my team very much. Three matches, nine points, is nothing new for us because last season was three matches and nine points.
“If I have to choose a word to describe my team, i would have to say “solid”.
“The players are good and motivated. They are on the bench waiting for a chance.
“We can look into perspective, last season we won against Leicester at home so that doesn’t make a difference but we had too many draws at home last season.”
Rashford always had the belief Manchester United would convert their chances.
United missed plenty of opportunities during the first 70 minutes, with summer signing Romelu Lukaku also seeing a penalty saved, but Rashford and Fellaini found the net after entering proceedings.
“We created a lot of chances in the first half and at the start it seemed like it was going to be one of those days,” Rashford said.
“The whole team stuck to the task well and, fortunately, we got the goal.
“When the chances are coming, I am always confident the goals will come. It was just a matter of when. Luck comes into play, but if we are playing the way we are the chances will come.”