Signings have not improved United, claims Mourinho
United, who finished second in the Premier League last term, brought in goalkeeper Lee Grant, defender Diogo Dalot and midfielder Fred, but Mourinho is thought to have wanted a new centre-back and has openly criticised the club's failure to back him.
Ahead of the Red Devils' league opener against Leicester City, Mourinho claimed he is working with essentially the same group as in 2017-18.
"It is the same, the same squad as last season," Mourinho told Sky Sports.
"We changed the goalkeepers with Lee because Joel [Pereira, loaned to Vitoria de Setubal] is such a good young goalkeeper that he needs to play.
"We changed Daley Blind [returned to Ajax] for a 19-year-old kid [Dalot] that we believe has the potential to play right-back or left-back. We changed Michael Carrick [retired] for Fred, so our squad is the same.
And we're back - our first @PremierLeague matchday of 2018/19! #MUFC pic.twitter.com/xKDhPOZjV9
— Manchester United (@ManUtd) August 10, 2018
"[Fred] is a midfield player, he's not a striker, not a central defender. He's a midfield player that technically is very good.
"In that sense, typically, the Brazilian player has a very rich luggage in technical terms and also in some static beauty movements of football. He's a player to really enjoy, if he adapts as soon as possible."
Mourinho believes he can now help his squad to get better, however.
He added: "There are ways to improve your team: one way is to spend a lot of money and to bring in lots of important players, another way is to work and that's the way we have to do it.
"I relish every challenge, it doesn't matter what, I love to work. That's the only thing I can promise, work hard. I am always confident, that's management."