Brighton won on Friday evening through goals from Kaoru Mitoma and Yankuba Minteh (2).
Maresca said afterwards: "Probably since I arrived that is the worst performance, especially in the moment we are in. We are fourth in the league and winning tonight you can go one point from third and make the gap to the rest bigger and the performance is not one you want to offer so we are very upset and sorry for the fans that were here.
"For half an hour I think we were in control but after this moment (Mitoma's goal) we looked like we could concede chances easily and we struggled to create chances. The reason why is because of the injuries in this moment especially with the strikers...important players are out but we need to find a solution.
"It is difficult when you don't have a proper number nine. So you always have to find a different solution. In the last third we struggled doing things that until a week or two ago we were doing well.
"This is the worst moment since I arrived but we are still there and we need to finish in the best way."