Liverpool manager Jurgen Klopp admits his side look fatigued in the loss to Brighton on Wednesday.
Steven Alzate's fortunate second-half strike was enough to separate the two sides.
The Reds are now seven points behind league leaders Manchester City heading into the two clubs meeting at Anfield on Sunday.
"Disappointed, nothing to smile about really," Klopp said after the game. "Tough one to take. A really tough week, two away games, two very intense games and tonight we looked really like we weren't fresh enough mentally and physically. A lot of moments where we gave the ball away too easily, in moments the boys looked tired mentally. I know they can pass the ball from A to B but it didn't happen, we made it easy for Brighton but they also did really well.
"Brighton deserved to win, no doubt about it. For me it's more important to find an explanation for why we lost this game and understand what happened here tonight. We didn't look convincing.
"Nothing good to say about it, it's over. Whatever set back we have to try and come back but we make more changes and then we have no rhythm so it's a problem. This week was hard, we lost our second home game in a row, but we can't change anything now we have to work with it."
