Benitez has been battling poor form and injuries in recent months and the Toffees were badly in need of a result ahead of hosting Liverpool in the Merseyside derby on Wednesday evening.
Everton though were second best in the contest at Goodison Park and slipped to a 4-1 defeat which piles further pressure on Benitez.
The Spaniard feels that being without Yerry Mina and Dominic Calvert-Lewin at present is having an effect and said post match on Prime Video: “We are talking about key players missing and maybe these key players are really important for the rest of the group to play at the level they can play.”
Benitez stressed the quality of the players that Liverpool have in their ranks must be taken into account, adding: “It’s always bad to lose, but when you lose against a team that have spent so much money and they have so many good players, sometimes it’s because you made mistakes and the other team is quite good.”
It was suggested to Benitez that Everton have splashed the cash in recent years, leaving the manager to indicate that transfer activity is an area which can be improved.
“I think this is something we can improve”, Benitez said.
Benitez was hamstrung by financial fair play regulations during the summer transfer window and was able to spend just £1.7m on improving the squad.
Fingers have been pointed by some fans at director of football Marcel Brands.