As everyone surely realises now, Liverpool are capable of swinging between the fantastic and the awful but, for the last two games, Rafael Benitez's men have been stunningly mediocre and for their second consecutive trip to the capital it cost them dear.
Elimination from the Carling Cup - thanks to Marco Reich's 72nd-minute volley in this third-round tie - may not rank high on Benitez's list of career disappointments but it has come at a bad time and losing is a bad habit the European champions have suddenly become too familiar with.
It came at Fulham on Saturday in the shape of a 2-0 defeat and although they at least managed to trouble the scorers here at Selhurst Park, they faded badly in the second half against a Championship side fifth in their division.
Benitez was tight-lipped afterwards and refused to criticise his players - having done exactly the opposite at the weekend - citing their hard work positively. He would only admit that their lack of goals is becoming a problem he is not worrying about, stating the obvious when he said that scoring goals would end that problem.
Having fallen behind to Dougie Freedman's header, it appeared to serve as the visitors' motivation and they duly equalised through Steven Gerrard. However, their removal from this competition was sealed 18 minutes from time. When the ball ran to the influential Michael Hughes, he was able to pick out Reich at the far post for the German to beat Scott Carson.
The story of Crystal Palace against Liverpool in the League Cup was, famously, once one of Clinton Morrison telling Michael Owen how to score goals. It was a story that saw Morrison end up humiliated although that was a feeling Liverpool were being acquainted with last night.
The Palace manager, Iain Dowie, did not dwell on Liverpool's undoing, instead saying: "This is a massive fillip for the club. We couldn't sit back and shut up shop. We had to play them." They did just that with Dowie praising his young midfield pairing of Tom Soares and Ben Watson for the not inconsiderable feat of cancelling out Dietmar Hamann and Gerrard.
Freedman saw an initial effort saved but eight minutes before the interval he gave the Eagles the lead as Palace helped themselves on the counter-attack. Hughes looked up from his station on the left and placed the perfect cross between the flat-footed Sami Hyypia and Zak Whitbread for Freedman to beat Carson, despite the goalkeeper getting a hand to the ball.
Julian Speroni, like Carson a second choice, had blocked Fernando Morientes and Steven Gerrard early on, but four minutes after Freedman's strike, he could not prevent an equaliser. Gerrard, back after three games out, moved forward and chipped a pass that Mark Hudson poked back into the path of the Liverpool captain and he produced a delightful curling shot to finish.
The names of such luminaries as Jamie Carragher, Djibril Cissé and John Arne Riise were missing from the Liverpool squad and while it was a policy Benitez adopted last season that served him well for most of the club's run to the Carling Cup final, before losing to Chelsea, it proved less fruitful here. With a Premiership game at the weekend, followed by the Champions' League next midweek, keeping his best players sharp was Benitez's intention here but these defeats are further dulling their edge.
Crystal Palace (4-4-2): Speroni; Boyce, Hall, Hudson, Borrowdale; Reich (Togwell, 84), Watson, Soares, Hughes; Freedman (Black, 78), Morrison (Andrews, 74). Substitutes not used: Kiraly (gk), Ward.
Liverpool (4-4-2): Carson; Raven, Hyypia, Whitbread, Warnock (Traoré, 77); Potter, Hamann, Gerrard, Kewell (Garcia, 65); Morientes (Sinama-Pongolle, 63), Crouch. Substitutes not used: Reina (gk), Josemi.
Referee: P Dowd (Staffordshire).