The Merseyside outfit dominated the opening exchanges as Blackburn portrayed all the hallmarks of a team desperately lacking in confidence.
The hosts' ball-retention was poor and they seemed bereft of ideas in the attacking third.
Liverpool looked to release wingers Benayoun and Ryan Babel at every opportunity and on 18 minutes Steven Gerrard sent Benayoun racing through on goal, only for Warnock to intervene with an outstanding challenge.
But Liverpool, lining up in a 4-5-1 formation with Robbie Keane dropped to the bench and Dirk Kuyt the lone striker, did not create another clear-cut chance in a half notable for the visitors' shortage of inspiration and cutting edge.
Ince proud of players despite defeat
Blackburn grew in belief and were unfortunate not to take the lead when Pedersen's long-range strike on 27 minutes was expertly tipped onto the woodwork by Liverpool goalkeeper Pepe Reina.
Reina was again called upon to save from Pedersen before half-time, this time palming a free-kick to safety, but the game became scrappy after the break.
The passing was, at times, woeful but Liverpool showed marginally more quality going forward and Robinson was forced to react well to repel Alonso's drive after 57 minutes.
Moments later Liverpool should have broken the deadlock but when Robinson spilled Gerrard's fierce strike, Benayoun could not follow up and Ryan Nelson scrambled the ball clear.
Blackburn were rocking and it came as no surprise when Alonso sidefooted past Robinson from just inside the penalty area.
Controlled display satisfies Benitez
The Spaniard pounced with a calm finish after Andre Ooijer, under pressure from Kuyt, had failed to deal with Gerrard's cross from the right and his fellow centre-half Christopher Samba was nowhere to be seen.
The Merseysiders could well have lost their lead on 75 minutes as Roque Santa Cruz rose to meet Ooijer's precise centre from the right but could not find the target with his header.
That miss proved coast because at the other end Benayoun collected Kuyt's pass on the right, skipped past Warnock's terrible attempted-tackle and lashed a low drive across goal and into Robinson's bottom right-hand corner.
In stoppage time Robinson, faced with Nabil El Zhar, was forced to rush his clearance and it fell to Albert Riera, who squared to Gerrard and the captain rounded off Liverpool's win.
Blackburn manager Paul Ince: "It was an exceptional performance. We have not got the three points but we have to take some positives from the game.
"It is always difficult against Liverpool but we matched them for long spells and that was pleasing.
"The scoreline was harsh and this might be the step we need to push on and get up the table."
Liverpool manager Rafael Benitez: "We have shown we can manage the pressure. When you have a game like this, you know you might have problems.
"But we were more clinical than other days and that is important with the Christmas programme coming up.
"We are in a very good position so it is vital we play with confidence and that the players pass the ball well."
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