Andy Robertson admitted Liverpool have got worse since the season resumed following the World Cup.
The Reds have won just once in six matches in all competitions since the turn of the year and were dumped out of the FA Cup by Brighton on Sunday.
Back at the scene of a 3-0 Premier League thumping a fortnight ago – which Jurgen Klopp described as the worst of his managerial career – Liverpool looked destined for at least a replay after Lewis Dunk’s lucky strike cancelled out Harvey Elliott’s opener.
But Japan star Kaoru Mitoma volleyed a dramatic winner to seal a 2-1 victory and knock the holders out.
“It’s bitterly disappointing. I thought it was a proper cup tie – end-to-end, both teams had chances,” left-back Robertson told ITV.
“We were slightly better than two weeks ago, but at the end of the day we’re out of the cup. It’s so disappointing.
“We need to start winning games. It’s easy to say and harder to fix. This season has been nowhere near good enough. We wanted a new start at the turn of the year. If anything we’ve been worse.
“You can’t put your finger on one thing that’s gone wrong, it’s more than that. You can tell we’re not confident in front of goal, we’re still a bit open defensively. We need to get our confidence back.
“I feel sorry for the fans. They were unbelievable and we’ve let them down again.”
Mitoma admitted his winner was the highlight of his Brighton career so far.
It was a spectacular strike, the winger bamboozling Joe Gomez as he controlled Pervis Estupinan’s cross at the far post before rifling the ball home.
“I think it’s my best moment so far, a great goal at the end of the game and we won because of this goal. I’m very happy,” he told Albion TV.
“We have the confidence now to play against every opponent. We prepared well and played tactically well. We’ll keep going but we have to stay humble.
“Every match is important. We focus on the next game. We have to keep going.”