Liverpool manager Jurgen Klopp admitted his side looked "mentally tired" after losing 1-0 at home to Brighton on Wednesday.
The German praised Graham Potter’s side but was disconsolate over his own team’s performance.
After going 68 games unbeaten at home, Liverpool have now lost back-to-back matches at Anfield and are seven points behind leaders Mancheste City, having played a game less.
Speaking to the BBC, he said: "Disappointed, nothing to smile about really. 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.
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"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."
Liverpool will face league leaders Manchester City in their next game on Sunday.
“We were not fresh tonight and that’s when you have to find a way," added Klopp.
"Each player can play better than they did tonight. I know them, it’s not because they didn’t want to. Something else must be the reason.
“If we make too many chances we lose rhythm. That leads to the situation where Brighton beat Liverpool and deserve it.”