Even in the pubs around Anfield, one of which has a mural of Rafael Benítez's legendary half-time speech in Istanbul in 2005, faith in the Liverpool manager has been known to waver. In the dressing-room, too, the Spaniard’s judgment has occasionally been questioned – not to mention a boardroom in which he is held with little, if any, affection – so do not underestimate the signficance of his first league victory over Manchester United in nine attempts.

Benítez had said before Saturday’s match that victory would be worth more than three points, referring to the momentum it would generate. That alone will not make Liverpool favourites to win the title, but consider how defeat might have been greeted on Saturday: the kneejerkers calling for his head on the radio phone-ins, the knowing glances exchanged in the dressing-room, the growing murmurs in the boardroom as another title challenge threatens to evaporate before it has begun. It might have been just a bad day at the office for United, but for Liverpool this was more than just a win.

It is not always easy to discern where Benítez is trying to take Liverpool, whether with an enormous turnover of players or his penchant for a kind of football by numbers. His players have been shocked at the treatment of Steve Finnan, who was sold to Espanyol against his wishes, and Xabi Alonso, who has been hawked around Europe in search of a buyer, but this victory, which was achieved without Fernando Torres and, for all but the final quarter of the match, without Steven Gerrard, required an abundance of character, particularly after they fell behind in the third minute, when Dimitar Berbatov, on his debut, set up Carlos Tévez.

“It was a massive win,” Gerrard said. “The first goal was a setback, coming so early on, but the reaction, character and workrate was fantastic.

You can understand when the manager says this was a game worth more than just three points. Beating a team like United is bound to help you. It shows you can beat anyone.”

And it shows the rest of the Premier League that United are not invincible. They will be a different proposition when Cristiano Ronaldo is back – possibly as a substitute against Villarreal in the Champions League on Wednesday or Chelsea in the league on Sunday – but does even Sir Alex Ferguson know how his team will take shape this season? On Saturday, they had Wayne Rooney on the right wing for much of the match, further marginalised by the presence of Berbatov, and none of the three midfield players who started the game finished it, Michael Carrick because of a foot injury and Paul Scholes and Anderson because of poor form. Nemanja Vidic had joined them in the dressing-room by the end, sent off for two bookings, and will miss the match against Chelsea at Stamford Bridge.

Ferguson conceded that his players had been unable to cope with the way Liverpool “tackled and harrassed” them. Whether it was Jamie Carragher getting to grips with Berbatov, Javier Mascherano and Alonso seizing control of the midfield or Dirk Kuyt and Robbie Keane constantly pressing the United defence, Liverpool looked hungrier and sharper in every department.

It was a wretched afternoon for United, with Ferguson saying that “we didn’t have one performer” and that “when people watch us, they will think it was a Conference team defending”. Certainly, Liverpool’s equalising goal was a gift. Alonso’s speculative shot looped up harmlessly off Patrice Evra, only for Edwin van der Sar to rush from his goal and palm the ball straight at Wes Brown, who deflected it in off a knee.

Van der Sar had a strange afternoon, making two excellent saves to deny Kuyt, but twice flapping at corners, twice kicking out of play and unwittingly causing Carrick’s injury by throwing the ball to the midfield player when he was surrounded by Liverpool players. Finally, he was beaten for a second time with 13 minutes remaining, when Ryan Giggs and Vidic dithered, enabling Mascherano and Kuyt to set up Ryan Babel in front of the Kop.

BenÍtez milked the celebrations – and, as he prepared for a postmatch meeting with George Gillett Jr, one of the club’s American owners, who could blame him? Last December, when the two men met after a home defeat by United, BenÍtez emerged grateful that he was still in a job. This time he could address Gillett from a position of strength. And while he still may not count on the support of the board, the dressing-room, if it was not so before, is right behind him.

Liverpool ratings (4-4-2)

J M Reina 7 Á Arbeloa 8 J Carragher 7 M Skrtel 7 F Aurélio 6 Y Benayoun 6 J Mascherano 8 X Alonso 7 A Riera 6 D Kuyt 7 R Keane 6 Substitutes S Gerrard 6 (for Benayoun, 68min), R Babel (for Riera, 72), S Hyypia (for Mascherano, 87). Not used D Cavalieri, A Dossena, F Torres, D Ngog.

United ratings (4-3-2-1)

E van der Sar 4 W Brown 6 R Ferdinand 6 N Vidic 5 P Evra 5 P Scholes 5 M Carrick 6 Anderson 4 W Rooney 5 C Tévez 6 D Berbatov 6 Substitutes R Giggs 4 (for Carrick, 46), O Hargreaves 5 (for Scholes, 66) Nani (for Anderson, 78). Not used T Kuszczak, J Evans, J O’Shea, D Fletcher.

Referee H Webb Attendance 44,192