Manchester United manager Erik ten Hag says the club "needs quality players" after conceding the standard of the squad is not good enough.
United were thumped 4-0 at Brentford - conceding four in the first 35 minutes - and have no points after two Premier League games.
Dutchman Ten Hag, who took over at Old Trafford in May, told Sky Sports the situation is a "difficult process".
"We have to provide higher standards than what we did today," he said.
"We are, as a team, in a difficult process. You expect a different start. It's not what we expected.
"We need new players. We need quality players. We are working on that and we'll do everything to convince them to come."
United have been involved in a long-running hunt for fresh recruits since the transfer window opened, following a disappointing campaign last year and a shock defeat at home to Brighton last Sunday.
Barcelona midfielder Frenkie de Jong has been the main target for Ten Hag but the 25-year-old has reportedly indicated he would prefer to join Chelsea if he left the Nou Camp.
A move for former Stoke and West Ham striker Marko Arnautovic attracted negative reaction from fans and was abandoned, as did interest in Juventus midfielder Adrien Rabiot - a transfer that appears close, despite significant disapproval from United's support.
"The team has to take responsibility. I feel really sorry for the fans - they did everything to support us but we let them down," said Ten Hag.
"You have to take responsibility on the pitch as a team and as individuals, that's what we didn't do. What I asked them to do is play with belief and take responsibility for the performance. We have to work on that.
"The manager is responsible as well. He has the main responsibility and I'll take that and work on that."