David de Gea says Manchester United's inconsistent run of form could be down to a 'lack of quality' in the squad.
"The team is what it is, and results are what they have been recently," De Gea told Sky Sports News. "It's true that the first half was horrible, probably one of the worst this year.
"The reaction of the team in the second half was important, but it's not enough. We should win these type of games to be on top, we need to win four or five games in a row to be at the top, but at the moment the team is not playing so well.
"We're giving it everything, we're trying to get those big wins that can put us high up in the table, but the truth is at the moment we're not consistent enough, there's much to train and much to improve.
"I don't think it's through any lack of effort, the boys are leaving everything out on the field in training and games. You could point maybe to a lack of quality in certain areas, but certainly not a lack of fight."
De Gea is one of the mainstays of Manchester United's squad, having entered his ninth season at the club since moving from Atletico Madrid in 2011.
The Spain international, who signed a new deal in September keeping him at Old Trafford until 2023 at least, admitted he is feeling settled in Manchester.
"The truth is I feel like at home here," De Gea said. "There are times when I am in Spain and I'm really looking forward to coming back here, at home in Manchester.
"We've been here for a lot of years and I feel like people appreciate me here, I've made a lot of friends and I'm thrilled to be part of this club.
"It's been a long time that I've been playing here and it's not an easy thing to keep playing at the highest level and to maintain that level.
"I personally hope that we can get more accolades in years to come by working hard and playing to that same high level."