Following the international break, United return to action at the Britannia Stadium having taken nine points from a possible nine so far this season, scoring 10 goals in the process and conceding none. Another win on Saturday will bode well for their chances of challenging for the Premier League crown, with Mourinho having gone onto win titles in all three of the previous seasons where his side has won their opening four games.
On Friday, the United boss was still waiting for the last members of his squad to return to Carrington following the international break. And having not trained with his entire squad for just over two weeks, he admits he does have concerns the lengthy break could have an adverse effect on his side.
"There is still one more training session," Mourinho told MUTV. "Not every player has reported yet, so today is the first time we are all together.
"I hope that these 15 days without us being together and working together, doesn't affect us too much," Mourinho added at his press conference. "I know it will affect [us]. I know that one thing is a week working with the players and working tactically and going through every principle of play to be ready for the weekend match; another thing is to have the players away and arriving step by step.
"I don't even see them all. Today is the first time I see them all together, and obviously today is not a day to work; today is just a day to make the decision and the selection and to travel to Stoke. But hopefully, we can keep a good level of play."
The strength of United's squad will get its first thorough tests in September with the club's return to the Champions League and a League Cup third round tie against Burton Albion waiting for them in the coming weeks.
Mourinho named almost identical starting XIs in his first three games this season – with the only exception being Anthony Martial's selection ahead of Marcus Rashford in the 2-0 win over Leicester City last time out.
The United boss expects that to change however and anticipates every member of his squad getting game time in the coming weeks.
"The players are ready to play, the decision to leave people on the bench is hard, the decision to leave people at home is hard. The fact that now we play every three days, in relation to that, I think is good because the players will feel now that they are all involved.
"I think, by the end of September every player [will have] played, every player [will have] started matches because it's the normal movement of the squad and that is not a problem at all - that makes my control of my human resources better, easier and simple. But the matches are difficult and we have always the risk of being unable to keep a winning run, which is really difficult to do."