Erik ten Hag claimed Manchester United's need for new signings was "clear" following their humiliating 4-0 defeat at Brentford, though he noted the Red Devils are underperforming given the quality already present in their squad.
Having watched his side slump to a 2-1 defeat to Brighton and Hove Albion last week, Ten Hag became the first United manager to lose each of his first two games in charge since John Chapman in 1921.
An embarrassing performance saw United go 4-0 down within just 35 minutes in London as Brentford scored with each of their first four shots on target.
United, who are bottom of the Premier League two matches into the Ten Hag era, have been linked with further additions in the transfer market, with Juventus' Adrien Rabiot a reported target amid their struggles to attract Frenkie de Jong from Barcelona.
Speaking to BBC after the chastening loss, Ten Hag said: "You have to be ready for a game and be ready for the battle as individuals and as a team. We have to push each other and bring the demands in because it is not good.
"It is clear we need players, but I don't want to think about that in this moment. The good players we had should have been better.
"I hoped for a better start, I have to believe because I have seen good things, but the two games from now are disappointing.
"We will analyse and we will move forward, but one thing is quite clear, we have to do things better.
"This team is good enough to beat Brighton and Brentford which we didn't, so we have to question ourselves."
Brentford's victory represented their first over United in any competition since a 2-0 FA Cup win in February 1938, and ended their seven-match winless run against the Old Trafford outfit.
And while United were plagued by individual mistakes throughout a torrid first half, Ten Hag accepted responsibility for another dismal performance.
"It's difficult for me. It's surprising when you start the game like this; in 35 minutes you concede four goals," he told Sky Sports.
"The team has to take responsibility. I feel really sorry for the fans – they did everything to support us, but we let them down.
"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."