It is always when they least anticipate trouble that Liverpool are at their most vulnerable.
Last night, they sneaked home courtesy of an Emile Heskey strike from close range with two minutes remaining but it could do nothing to disguise the threadbare nature of their performance.
The prospect of Houllier resting some of his more important players - allied to the foul weather and the unknown opposition - meant that Anfield was awash with empty seats.
Even though Michael Owen was again absent because of injury, Houllier was sufficiently confident to demote Sami Hyypia, Nick Barmby and Gary McAllister to the substitute's bench .
The guile of McAllister in particular was missed as Liverpool diligently set about cracking a walnut with a sledgehammer.
If Robbie Fowler had been fit he would certainly have scored after 13 minutes, for having reached a Vladimir Smicer cross from the right, scoring appeared to be an easier option than missing. But miss he did, his header from no great distance drifting up and over.
The inescapable fact that Fowler was badly out of sorts made the events of the 54th minute all the more curious, when Liberec decided to start handing out the gifts. As he shaped to steer a Smicer corner goalwards, Dietmar Hamann was nudged, no more, by Jiri Stajner. A penalty was the decision.
Fowler decided to accept the responsibility but his kick comfortably cleared the crossbar.
At last the enormity of the situation began to dawn on Houllier's lethargic troops and as the Czechs tired, Markus Babbel and Smicer both went close before Heskey ended the torture.
LIVERPOOL: Westerveld, Henchoz, Ziege, Babbel, Smicer (Barmby 69), Heskey, Fowler, Murphy (McAllister 69), Berger, Hamann, Carragher. Subs Not Used: Song, Hyypia, Arphexad, Camara, Traore. Booked: Murphy, Babbel. Goal: Heskey 88.
LIBEREC: Hauzr, Capek, Michalik, Lexa, Kozuch (Bakes 83), Stajner (Jun 72), Liuni (J Nezmar 80), Johana, Janu, Neumann, Pilny. Subs Not Used: Breda, Beno, Silney, T Barta. Booked: Johana.
Referee: M Busacca (Switzerland)
