Jamie Mackie's dramatic second-half stoppage time winner stole victory for QPR, who came from two goals behind to record a remarkable victory at Loftus Road.
On a night that R's fans won't forget in a hurry, it looked as though Liverpool would be taking all three points back to Anfield after Sebastian Coates and Dirk Kuyt put the visitors two goals to the good in the second half.
Rangers, however, had other ideas - and after Shaun Derry pulled a goal back for the home side 13 minutes from time - Djibril Cisse was on hand to put the Hoops on terms on 86 minutes.
And the drama wasn't finished there. Substitute Mackie capped the unlikeliest of comebacks, with his 90th-minute strike pulling the R's out of the Barclays Premier League relegation zone.
Mark Hughes made two changes to his Hoops side from last weekend's 2-1 defeat at Bolton Wanderers, with Luke Young and Adel Taarabt replacing Clint Hill (back) and Shaun Wright-Phillips respectively.
Paddy Kenny was in goal for QPR, who deployed a 4-4-2 formation.
Young, Nedum Onuoha, Anton Ferdinand and Armand Traore lined up in defence.
R's skipper Joey Barton began from the right-hand side of midfield, with Derry and Samba Diakite in the middle. Taarabt, meanwhile, operated out wide on the left.
Cisse - who scored his second goal in just three Rangers appearances at the Reebok Stadium 11 days ago - partnered Bobby Zamora in attack.
Fresh from their victory over Stoke in the quarter-finals of the FA Cup on Sunday, the visitors began with a real sense of purpose.
It took only four minutes for Kenny Dalglish's side to fashion their first attempt on target - that thanks to a defensive mistake from the home side.
It was a chance that Liverpool really should have taken. Onuoha misread a Charlie Adam pass which put Luis Suarez in the clear, but the Uruguayan hot-shot was to be denied by a fine low stop from Kenny.
Five minutes later, Steven's Gerrard zipped slide-rule pass freed Stewart Downing in the box, only for Derry to produce an excellent sliding intervention to stop the England wide-man from getting a shot away.
Rangers had to defend for their lives early on. Indeed, they had Ferdinand to thank for a brave block to thwart Kuyt from close range on ten minutes, after Gerrard's corner eventually fell into his path.
But the R's would finally fashion their first attempt of note on the quarter-hour mark.
Zamora and Cisse combined wonderfully well, exchanging passes before the latter pulled an effort wide of the left-hand post.
At the other end, Martin Skrtel went close with a header nine minutes later, after meeting Adam's corner.
There was a heart in mouth moment for Dalglish's men shortly after. Traore out-paced his marker down the left before his subsequent cross forced a miscued clearance from Jose Enrique that only just went past upright.
Despite Liverpool's early dominance, Rangers got better as the half wore on.
Cisse went exceptionally close to putting the R's in front in that improved period of play, crashing an effort inches wide of the right-hand post after evading the challenges of Adam and Jay Spearing.
The French striker would also produce the first attempt of the second period, with his effort from distance forcing a comfortable low save from Pepe Reina just a minute after the half-time break.
But it was Liverpool who would strike first thanks a sensational effort from substitute Coates.
Gerrard's corner eventually led to Downing seeing his shot cleared off the goal-line, before Coates was first to the loose ball to thunder a sublime volley into the roof of the net.
Downing would also go close for the visitors three minutes later, seeing his rasping drive gathered at the second attempt by Kenny.
The Reds' opener prompted Hughes into a change on 62 minutes, bringing on Mackie to replace Barton.
Though it was Liverpool who would go closest following the substitution.
Downing saw his shot - that appeared to be creeping into the bottom right-hand corner - superbly tipped around the post by Kenny.
The Merseysiders would soon double their advantage on 72 minutes.
Suarez's effort crashed off the post, before Downing's subsequent shot forced a fine low save from Kenny.
Kuyt was then first to react to the loose ball, racing in to slide home a Liverpool second.
But Rangers ensured there would be a grandstand finish, halving the deficit on 77 minutes.
Taarabt's corner from the right found Derry at the back post, who rose highest - albeit on the stretch - to head home from close range.
Staggeringly, the R's put themselves on terms with just four minutes left on the clock.
Taye Taiwo's centre from the left was of perfection to find the head of Cisse, who stole in to nod QPR level.
Loftus Road was rocking - but there were scenes still to come that will live long in the memory, after Rangers capped an outstanding comeback in second-half stoppage time.
A ball from deep put Mackie in the clear and he kept remarkable calm, driving into the box before expertly sliding the ball past Reina for the winning goal.