Everton boss Sean Dyche admits they weren't at their best for Saturday's FA Cup defeat to Luton.
Luton won 2-1 to reach the Fifth Round, with Cauley Woodrow proving the matchwinner.
Dyche said: "It was an ugly, tight game, not much in it, won on two set pieces again unfortunately. A last minute goal, and that hurts you.
"Second half was better, first half we weren't close to it. We need to find the moments of real quality. We are a bit stretched at the moment. We changed the system later in the week which was difficult as well. I thought we performed well enough at times to win the game.
"Second half we looked a more dominant force when the ball went longer in to the front line. No lack of effort. A tight, awkward, ugly game. I don't know what is going on with VAR, Dominic Calvert-Lewin clearly had two hands in his back and somehow we didn't get a foul. One of their lads went in on Dwight McNeil in the first half and we didn't get anything for that. I have to mention it.
"Our set-piece record is very strong but unfortunately not against these. They created a lot of chances that way in the league game. There are things we definitely need to iron out."