Jose Mourinho is convinced Manchester United will be stronger this season but is not getting carried away with their impressive Premier League opener.
United justified some of the optimism that has built up over the summer at Old Trafford by thrashing West Ham 4-0.
The performances of new signings Romelu Lukaku, who scored twice, and Nemanja Matic particularly caught the eye but the team was still not playing entirely to Mourinho's satisfaction.
He said: "Many times last season we deserved to win and we didn't, so the fact we won the match was the most important thing.
"I think the quality of our performance, based on the confidence levels, was really high but I am not going to say the performance was perfect because it wasn't perfect. We made our mistakes and have room for improvement, obviously.
"But it was a solid performance. We had good stability, good confidence levels and desire to play until the end. So good, really good.
"Now our challenge is to keep these confidence levels. I think we can be a better team than we were last season."
West Ham played deep and seemed intent on damage limitation from the outset. That allowed a hungry United side to dominate.
The Red Devils showed bite, energy, creativity and strength and fully merited the lead when Lukaku smashed in off the post after 33 minutes following a quick break.
The £75million record buy headed a second early in the second half and was denied a hat-trick by a fine block by Pablo Zabaleta. United spurned several other chances before Anthony Martial and Paul Pogba added two more in the closing minutes.
United's third summer signing, central defender Victor Lindelof, did not even make the bench after a difficult debut in last week's Super Cup against Real Madrid but Mourinho says the Swede's time will come.
He said: "I think Real Madrid was too early for him. He played because (Phil) Jones and (Eric) Bailly were both suspended. The difference between Lukaku and Matic is that they have years and years of experience of Premier League.
"In 2004 I bought a phenomenal central defender to England, Ricardo Carvalho. He was one of the best central defenders in the last decade in the Premier League. But he struggled and it was difficult for him to come and adapt in the beginning.
"Victor needs a little bit of time and he is going to have that time. Let's go step by step because Victor is a fantastic player."
West Ham also enjoyed a productive summer in the transfer market but their performance was a subdued one. The emphatic nature of the defeat could also damage confidence but manager Slaven Bilic is determined to ensure that does not happen.
Bilic said: "We are not going to forget about this game and say it just happened. We have to analyse this game but on the other hand it is the first game of the season. We can't lose confidence just because of one game and especially if that game is against Man Utd.
"We conceded the first couple of goals from our own big mistakes, especially the first goal. We were all right until then. After that it is very hard to play against them, especially when they start to play on the counter-attack or are waiting for your mistakes or to get the ball.
"We can't lose our confidence because we lost here, no matter how this result is bad for us."