"I'm not confident", he told a pre-match news conference when asked whether another signing might be made.
The 25-year-old signed from Shakhtar Donetsk in a deal worth around £50 million and joined up with United for part of their preseason tour of the USA after a post-World Cup break.
"I will have to focus on the players I have and, in relation to this first couple of matches - maybe three matches because after Spurs there is [the global break] and a couple of weeks to recover people and to prepare people - it is better to focus on the players that are available for the first match".
Mourinho's transfer targets were not shared by the United board.
Economic turmoil hits Turkey, US bank stocks react
The United States is the biggest destination for Turkish steel exports with 11% of the Turkish export volume. The lira hit a record low of 6.24 per dollar on Friday, before recovering to 5.94, down 7 percent on the day.
The Daily Mail reports that Mourinho was left "furious, angry and frustrated" after yesterday's failed transfers.
"It was my first goal and that is all that was important, it doesn't matter how I scored", he said. So, when you repeat 1,000 times that my relationship with my players is not good, it's a lie that repeated 1,000 times is still a lie.
The Ecuadorian wing-back, who recently turned 33, has been one of the most reliable players during Mourinho's two-year reign in Manchester.
"But he's got great experience, he's been at top clubs, he's been in hard positions before, he's in a hard position now I think, but he needs to try to find a way to get out of it". Or you believe in the pundits and go with what they say. "It depends on the music, but words for me don't come easy".
Tom Brady close to signing contract adjustment with New England Patriots
Guice injured his left knee at the end of a first-quarter run in Thursday's preseason opener against the New England Patriots . Gruden has said there's competition for the No. 1 job along with Thompson, who's coming back from a broken fibula.
Sanchez said he expects the Brazil midfielder to be a great addition to the squad, which finished second in the Premier League last season.
He didn't give United enough of a threat against a very weak looking Leicester right-hand side and when he did get the ball, he was often wasteful and sloppy making the wrong decision more often than not.
West Ham signed Spanish striker Lucas Perez from Arsenal to complete a near 100-million pounds summer spend.
The midfielder who amassed a total of 718 appearances for the club questioned the Portuguese manager's idea of a "new-look" for United, saying former manager Sir Alex Ferguson has already left the club with a flawless recipe for success.
New ‘Doom Eternal’ Details, Gameplay Footage From QuakeCon 2018
One interesting thing about DOOM Eternal is that it will allow players to take over demons and "invade" another player's game.