Manchester United manager Jose Mourinho admits that his side's performance against Leicester City was far from "fantastic".
The Red Devils needed a late Zlatan Ibrahimovic goal to lift the FA Community Shield at Wembley.
It was the perfect day for them as it was also announced that midfielder Paul Pogba will join the club after leaving Juventus.
But Mourinho says there is still a lot of work to be done ahead of next week's season opener.
"The first half was much better than the second which doesn't surprise me because the team is not fit enough and in condition to keep the stability in the game," Mourinho told reporters.
"In the second half when they increased the pace by bringing on three quick players in Gray and Musah plus Vardy, they changed the game to their style.
"I think it's an important victory but of course we have lots of work to do. I would be not ambitious if I say that we had a fantastic performance because it was not a fantastic performance.
"It was a possible performance for this moment of the season. Some of these guys today they have one week of training - Martial, Ibrahimovic, Fellaini.
"The other ones had two weeks, no pre-season in China, a very bad pre-season, so I think step by step we are changing, but I think it's always important to start with a trophy."
"Zlatan will be more dangerous when we are more dominant and play closest to the box. Zlatan is not a very fast player to play 50 metres away from the box like where Vardy can be dangerous.
"Zlatan needs the team to play, he needs the team to produce and he needs the team to be arriving in the final third. It's something that we also have to change because the profile of this team was more about possession of the ball. Even arriving in crossing positions, the team normally plays back again and tries to change to the other side.
"We are trying to change. The reality is the second goal is a great example of that.
"I think it's [Fellaini's mistake is] the mistake of the slow pitch.
"Before the game starts I put my hand on the surface and I thought, 'Wow, we are in trouble because we want a fast pitch and the pitch is really slow.' Good pitch but slow. I don't know if they put water on and the atmosphere killed the water immediately or if they forgot to do it but the reality is it was very slow.
"So Marouane gives a backpass and the ball slowed down and Vardy smells everything and is really fast. I think Bailly is the perfect opponent for people like they have because he is as fast as they are.
"I know the player he is but you always have a little question mark when a player comes from a completely different level and plays his first match for Manchester United officially at Wembley with these responsibilities, without Smalling. The way he played I think he was really good but I have to say Daley also gave him the stability he needs."