Erik ten Hag has warned Manchester United fans to prepare for a slow start to the season while his players get up to speed.
Ten Hag was without a number of key squad members for the tour of the U.S. because of international commitments, including Bruno Fernandes, Lisandro Martínez and Alejandro Garnacho.
The Dutchman has said he won't "take risks" with players ahead of the Community Shield against Manchester City on Saturday and suggested it may take time to get going when the Premier League season starts.
"I can see this because we didn't have time together," said Ten Hag.
"We have to work on our game model to find the patterns. It was a break, they all played Euros, Copa América so they were in different teams, with different game models and different patterns.
"Now we have to bring this together. It is complicated. I am not the only one who has to deal with this problem but there are also teams with less international players, they can make a proper preseason so they are probably ahead of us. We have to deal with this in the coming weeks without dropping points."
Ten Hag will be without injured pair Leny Yoro and Rasmus Højlund for the start of the season. Harry Maguire, Luke Shaw, Victor Lindelöf and Aaron Wan-Bissaka are all doubts to face City which could leave just Martinez, Jonny Evans and Diogo Dalot as United's only fit senior defenders at Wembley.
Their Premier League campaign kicks off with a home game against Fulham on Aug. 16 and Ten Hag said he's not prepared to risk more injuries to lift the Community Shield.
"We know already we can beat City and that is not dependent on the result on Saturday that will not change that belief," he added.
"The FA Cup was a higher occasion than the game on Saturday. Nevertheless, we want to win but we showed on occasions we can beat City.
"We have that belief but we don't want to take a risk with players and lose them for long periods because that is what we have to take from last season because when you are getting in a pattern when we are missing many players with injuries from the same team unit that affects the results."
"We want to get results and for that players have to be available."
Despite heavy speculation over his future at the end of last season, Ten Hag was backed this summer with a new contract through 2026.
And former United striker Robin van Persie has backed Ten Hag and new assistant manager Rudd van Nistelrooy to bring greater success to Old Trafford.
"I had the luxury of spending a few days with him on the pitch. Two times," Van Persie, who recently took charge at Heerenveen told ESPN Netherlands. "Two years ago and last season. I know his modus operandi. I know what he is like as a person. I know what he is like as a manager. I know how challenging he is at Manchester United.
"Manchester United is a great club. A lot of new people are there now. It's a very big challenge for him on and off the pitch. I know he can do it. I believe in Erik. I know Ruud van Nistelrooy too, of course. Erik has an incredibly good one there. Ruud is loyal, Ruud is a lover, works incredibly hard and can teach strikers a thing or two, I think."
Ten Hag led Man United to an FA Cup and Carabao Cup in his first two seasons but a first league title since 2012-13 has remained elusive.
"He's won two cups, he's winning awards in between and he's building his style of play," Van Persie added. "I've seen the boys. They want to work for him. Hopefully he can make the step so that this ends up in a title. That's what I hope for him."