Jose Mourinho is yet to be satisfied by Manchester United's dealings in the transfer window, despite the arrivals of Romelu Lukaku and Victor Lindelof.
United missed out on signing Antoine Griezmann and have decided against bringing in Alvaro Morata up to now, while a reported chase of Eric Dier is expected to fall short due to Tottenham's demands.
United beat Chelsea to the signing of Lukaku, who netted his first goal against Real Salt Lake on Monday, but Mourinho is targeting two more signings - with Ivan Perisic and Nemanja Matic thought to be top of his wishlist.
"We always want more," Mourinho told ESPN. "We always feel there is room to improve, and I cannot say that I am happy with our transfer window.
"What I can also say is that it is a difficult transfer window and I don't blame anyone - it is just a reality of things. The market is going in such a direction that many players are difficult to get, not to say impossible.
"Every club is powerful and they don't want to sell or their demands are really high, so the market is difficult.
"What I will say is that, a long time ago, we thought about four players to strengthen our squad, but it is really hard to do it. If we do the third and forget the fourth, I would be quite happy with that because I know it is difficult.
"At the moment we have Lukaku and Lindelof, two players I know well. I worked with one before and the other is from the Portuguese championship, which I follow every weekend.
"I am happy with them and I know that they will succeed at the club.
"The market ends on August 31, so there is plenty of time, but obviously, the objective for me as manager is always to have the players as soon as possible and try to coach them in the team and develop the team with them and Lukaku and Lindelof arrived to train in time for day one."