their sixth in seven games -- and finishing with nine men after Philipp Degen and Jamie Carragher were dismissed.
And in the fall-out from defeat, Benitez has been accused of fundamentally failing to understand what matters most to the Merseyside club.
With the score at 1-1, Benitez withdrew his goal-scorer and most likely match-winner Fernando Torres in order to protect the striker's fragile groin ahead of this week's Champions League trip to Lyon. Then, when his side had fallen 2-1 behind, he took off Yossi Benayoun, Liverpool's second most creative player on the day.
With Liverpool's hopes of progressing from the group stage in Europe hanging by a slender thread after successive defeats, the moves were perhaps understandable, especially as Torres has been playing with pain-killing injections.
But in the eyes of some Liverpool supporters, the manager committed the unforgivable act of apparently giving up on the Premier League title.
And despite the club's roll-call of success in the European Cup, the trophy that most Kopites want to see returned to the Anfield trophy room is the domestic championship.
Liverpool last won the league in 1990, and in the intervening years have been forced to watch as hated rivals Manchester United have dominated the modern era, winning eleven titles in 16 years to draw level with the Anfield club's all-time record of 18 championships.
If anything has focused the mind of the club's frustrated supporters, it is the thought of United eclipsing them at the head of the honors board.
Yet the reality now is that after five defeats in their opening eleven league games, Liverpool's ambitions are unlikely to extend any further than a top-four finish.
And that has triggered louder rumblings of dissent this weekend including, significantly, strong criticism of Benitez from former player Ronnie Whelan, who won six titles and a European Cup during the 1980s.
Speaking on Irish television, Whelan made it clear he believes it is time for a change.
"It's all gone wrong with the manager," said Whelan on RTE's Premier Soccer Saturday. "He's shown exactly where his priorities lie.
"He wants to win the European Cup. He wants to be the man who wins the European Cup so he can get a job anywhere in Europe.
"I think after winning the European Cup with Liverpool he will get a job in Europe anyway but, for me, now, his days have got to be numbered at Liverpool.
"He showed me that he wants to win the Champions League and that's all he cares about -- because of the team he picked.
"He's taken players off who are the only players who are going to give you a chance of winning the game. And he drags them all off because he's got a game on Wednesday.
"He's putting all his eggs in one basket. If he loses in Lyon, he probably won't qualify for the Champions League knockout stages. So, he's out of the Champions League, he's not going to win the Premier League anyway -- so he's messed up completely."
An outburst from a former player may not carry much weight elsewhere, but at Anfield, there's a proud tradition commonly referred to as "the Liverpool way."
It's a tradition of keeping things in-house, of maintaining loyalty to the club and avoiding the kind of strife and upheaval that turns many other clubs into a laughing stock.
Managers at Liverpool aren't hounded out, they tend to be eased to one side once it becomes clear their time has come.
That's the way Gerard Houllier was moved on to make way for Benitez in 2004 after the club's board decided that after six years, the Frenchman was no nearer to building a title-winning squad.
And ironically, Houllier left insisting that his position had been undermined by criticism from a number of the club's former players.
It's not just Whelan who has voiced strong opinions this weekend, though. The message boards and phone-ins have been humming with the outpourings of disgruntled fans.
The cases for and against Benitez carrying on are relatively straight-forward.
The manager's record in the transfer market together with his occasionally bewildering tactics and team selection have brought plenty of criticism.
Set against that is the Benitez's success in winning the Champions League in 2005, last season's achievement in finishing runners-up to United and the claim that the Spaniard is attempting to close the gap on big spending rivals with only a fraction of his opponents' transfer budget.
What is undeniably true is that too many of the players who performed so well last season have been nowhere near their best this time around.
Real Madrid's offer of £30m for Xabi Alonso proved too good to turn down in the summer, but Javier Mascherano has failed to step up and fill the gap left by the Spain international.
Carragher has looked a shadow of his former self in central defense, while Lucas and Ryan Babel have failed to progress.
And, most tellingly, Torres, Steven Gerrard and Alberto Aquilani -- who finally made his debut last week after arriving in a £20m move from Roma this summer -- have been hampered with injuries.
Yet while all clubs suffer injuries to good players, top clubs have respectable cover. And not many people outside the confines of Benitez's office would regard David Ngog, Andriy Voronin, Babel or even Dirk Kuyt as worthy deputies for Torres.
Last week's victory over Manchester United bought the manager breathing space, but that will quickly disappear if results don't improve against Lyon and then Birmingham City and Manchester City.
Benitez has a notoriously thick skin. He'll need it if he conjure wins quickly.
Ian Winrow is a London-based football journalist and columnist for GlobalSoccerCenter.com.
