A goal from Danny Murphy five minutes from time here last night dramatically halted Manchester United's march after eight successive wins and reminded everyone there is even greater possibilities in the title race.
The midfielder's chip over Fabien Barthez from Steven Gerrard's lofted pass enabled Liverpool to celebrate their second successive league double over their fierce rivals.
This had been United's chance to cash in on all the other contenders' apparent desire to pause for breath - or in the case of Liverpool mouth-to-mouth resuscitation. Having regained the leadership over the weekend, moreover, the champions were keen to restore some familiar daylight between themselves and the pack.
United's ability to win eight games against, in the main, the Premiership's lower-middle class should not have surprised anyone. More remarkable was the speed of the decline which before last night had seen Liverpool, top in mid-December and at one stage 11 points ahead of United, subsequently take only eight points out of a possible 27.
Liverpool's determination could not be questioned. Steven Gerrard earned a yellow card after only 40 seconds when he fouled first Ruud van Nistelrooy, then Ryan Giggs.
A number of their early tackles suggested Phil Thompson, Liverpool's acting-manager, had offered some old-fashioned advice: "Get stuck in!"
Certainly it was in Liverpool's interest to deny United their more fluent rhythms. And the regularity with which they withdrew eight men behind the ball meant that United's movements had to achieve consistent width if they were not to be crowded out.
Usually teams who try merely to contain United here spring a leak sooner or later. Last night it took United about 15 minutes to get their passing together whereupon Giggs dragged a shot wide of the far post after one of Mikael Silvestre's hard-driven, low crosses from the left had ricocheted off Stephane Henchoz.
With the deep-lying Juan Veron supplying long, telling passes in the manner of a quarterback, and Paul Scholes and Roy Keane quick to link up with Giggs and van Nistelrooy, Liverpool were forced to defend deeper and deeper.
Midway through the first half, after Fabien Barthez had punched away a corner, a typically brisk United counter saw Giggs break away before Scholes accepted a return pass from David Beckham to send another shot just wide.
With Scholes again going close after another exchange of passes, this time with Giggs, United remained reasonably chipper. But the enduring fragility of Ferguson's defence cannot afford too many misses up front, and just past the half-hour a mistake by Scholes emphasised their need for a goal.
Pouncing on the error, Dietmar Hamann strode confidently at United's defence. He was dispossessed by Laurent Blanc's sliding tackle, but the ball went straight to Michael Owen, whose cross-shot beat Barthez only to roll just wide.
Beckham's dangerous, inswinging free-kick from the left was headed away by Henchoz before it could trouble Jerzy Dudek, but by half-time United's football had lost some momentum while Liverpool were establishing an attacking presence of their own.
With Gerrard and Hamann continuing to move forward with greater ambition in the second half this was now a much more even contest. And still little threat near goal had come from van Nistelrooy, which reflected great credit on Liverpool's centre-backs, Henchoz and Sami Hyypia.
Giggs, with his quick changes of pace and direction, remained United's best chance of breaking Liverpool down. But since he spent most of his time in the middle last night it meant his team was deprived of its greatest weapon.
Liverpool began the second half in a more positive mood and were knocking the ball about with growing confidence.
United lost their way after their blistering start to the game and van Nistelrooy was receiving little or no service as he sought his record-breaking ninth goal in as many games.
United's passing began to go astray and a feeling of frustration also began to emerge from the fans, who had come expecting yet another win.
The home fans eventually had something to get excited about when Beckham curled a shot just wide and Dudek punched away a rocket from Juan Sebastian Veron.
Nicolas Anelka replaced Owen 13 minutes from time and within a minute he almost scored when Barthez saved his shot at the near post.
Seconds later Barthez made an even better stop when he kept out a piledriver from John Arne Riise.
Liverpool's greater ambition was rewarded on 85 minutes with the winning goal.
Murphy, who has had to endure much criticism in recent weeks, collected Gerrard's pass, lifted the ball over Barthez and scored.
United tried to mount one of their trademark comebacks and Dudek saved a Giggs header from their best effort before referee Graham Barber blew to seal another famous win for Liverpool.
... Guardian Service
MANCHESTER UTD: Barthez, Phil Neville, Gary Neville, Blanc, Silvestre, Beckham (Solskjaer 87), Keane, Scholes, Veron, van Nistelrooy, Giggs. Subs Not Used: Carroll, Wallwork, O'Shea, Butt. Booked: Veron.
LIVERPOOL: Dudek, Wright, Henchoz, Hyypia, Carragher, Murphy (Berger 88), Hamann, Gerrard, Riise, Heskey, Owen (Anelka 77). Subs Not Used: Arphexad, McAllister, Biscan. Booked: Gerrard, Carragher. Goals: Murphy 85.
Referee: G Barber (Tring).
