The Red Devils kicked off the new Premier League season with a 2-1 victory over the Foxes.
"I think football is changing and managers should be called head coaches".
"I've been unlucky because I've had a few ups and downs, with different managers, but I would say I've never been out of shape".
Martial fell down the pecking order at United last season with Mourinho preferring Marcus Rashford and Alexis Sanchez as options.
After sealing deals for Fred, Diogo Dalot and Lee Grant by early July, last season's Premier League runners-up were unable to add further despite the Portuguese's explicit desire to bring in two more players.
"We have to wait for end of November, beginning of December to understand how things are going and if we can fight for the title".
Mourinho believes United should be content with a win over a side who spent more money than them in the close season. "I like challenges, I want to progress and win more trophies". "I think we are more the head coach than the manager", Mourinho told Sky Sports. Every team is a good team, forget the name, forget the history, forget the shirt.
"A good match. A match where I needed six changes not three".
Pogba leads Man Utd to winning start
Mourinho also confirmed Pogba had his blessing to take the penalty after what appeared to be a disagreement with Alexis Sanchez . I needed more changes, but I couldn't so it was not easy to manage the game from the touchline point of view.
Speaking afterwards, Pogba said: "Luke is someone who works very hard in training. We thought a maximum 60 minutes but he managed 80". I think one defensive mistake and probably the linesman could help him and give a free-kick against Leicester.
Of Pogba's penalty, which came after just 75 seconds, he said: "A very good penalty taker".
The Frenchman, who had been linked with a possible transfer window move to Barcelona, said he remained hungry for more success.
Despite no new defenders, Mourinho insisted he was happy with his squad, but accused critics of lying about any turmoil.
Shaw forced a save from Kasper Schmeichel just past the 40-minute mark, settling a pass from Juan Mata after some nice build-up play from United before firing right at the Leicester keeper.
The French forward was left out of France's World Cup squad prior to their successful campaign in Russian Federation, a decision which came as no surprise after a disappointing 2017/18 season, and his pre-season has been blighted with speculation that manager Jose Mourinho is unhappy with him.
However, the second goal of the game would eventually come for the hosts late on, via an unlikely source.