Liverpool breathed new life into the Premier League title race with their four-goal demolition of Manchester United at Old Trafford.
Even Rafa Benitez had admitted that anything other than victory for his side would see them out of contention to end their 19-year wait for the English crown, but few could have predicted what transpired on a memorable afternoon.
United went into the game on the back of an 11-game winning streak in the Premier League, during which they had conceded just two goals, but were dismantled by an energetic and vibrant visiting side.
Red Devils defender Nemanja Vidic endured what must rank among the worst games of his Old Trafford career as he blundered to allow Fernando Torres the chance to cancel out Cristiano Ronaldo's penalty opener before seeing red for hauling down Steven Gerrard 14 minutes from time.
Gerrard had already put Liverpool in front on the stroke of half time after being felled by Patrice Evra, before Fabio Aurelio made Vidic's day worse by curling home the free-kick after the Serbian's early exit with Andrea Dossena lobbing a late fourth.
It was Sir Alex Ferguson's heaviest home defeat since QPR triumphed by the same scoreline on New Year's Day 1992, but the Scot knows his side remain in the box seat with a four-point advantage and a game in hand.
Liverpool must now hope that they have shattered the air of invincibility which has surrounded United since the turn of the year, and are also required to put an end to their own failings of triumphing in the big games before blundering against lesser opposition.
Benitez's men still trail Chelsea on goal difference after Guus Hiddink's troops edged back into second spot on Sunday courtesy of a single goal victory against poor travellers Manchester City.
Michael Essien, tipped to have a major impact on the run-in after his return from injury, scored the crucial winner on his first Premier League start after returning from a serious knee injury.
Hiddink admitted after the match that the added tension in the title race could aid the chasing pack, while City boss Mark Hughes defended record signing Robinho after another display away from Eastlands which did little to justify his £32.5million price tag.
Martin O'Neill was another manager forced to defend one of his players, but with substantially greater justification, after Gabriel Agbonlahor was singled out by Aston Villa fans during the 2-1 home defeat by Tottenham.
Agbonlahor's overall contribution to Villa challenging for a UEFA Champions League berth appears to have been forgotten by section of supporters either unwilling or unable to see beyond a current dip in personal form which has coincided with the Midlands club's recent slide.
Spurs eased their relegation fears courtesy of an early strike from Jermaine Jenas and a second soon after the interval which Darren Bent simply could not miss. Perhaps he has had some tips on finishing from Mrs Redknapp.
With just one point to show from their last four games, Villa have surrendered the initiative to Arsenal, who finally found their Emirates Stadium shooting boots in Saturday's 4-0 success over Blackburn Rovers.
Andrey Arshavin broke his duck for the Gunners, although his close-range opener owed much to a defensive deflection from Andre Ooijer, but there were no arguments over his second which demonstrated the guile and skill which persuaded Arsene Wenger to secure his services in January.
The much-maligned Emmanuel Eboue stepped off the bench to score twice in his seven-minute cameo display to leave Sam Allardyce's visitors only one point above the drop zone.
The two matches tipped as relegation six-pointers before the weekend produced two tense draws as Middlesbrough snatched a last-gasp point at home to Portsmouth and Newcastle came from behind at Hull City.
Boro remain in the drop zone but looked set to be cast further adrift as they trailed to Peter Crouch's volleyed opener at the Riverside before seeing Matthew Bates dismissed after a second yellow card for diving.
But with the clock ticking down Marlon King pounced from close range to bring the scores level and there was still time for Afonso Alves to miss a one-on-one with David James in a dramatic finale as Pompey sneaked up to 17th on goal difference.
Newcastle have a similarly slender margin keeping them out of the bottom three after drawing 1-1 with Hull City, whose home form remains the worst in the division, after Steven Taylor's deft volley cancelled out Geovanni's first-half header.
Stoke have now slipped back into the relegation places despite a battling second half display against Everton at Goodison Park, with the Toffees still in contention for a top four finish after a 3-1 triumph.
Thomas Sorensen hardly covered himself in glory for Everton's first two goals, allowing Jo's shot to squirm under his body before palming a Tim Cahill header straight into the path of a grateful Joleon Lescott.
Ryan Shawcross headed the Potters back into contention after the break but as they pressed for an equaliser Tony Pulis' visitors were undone by the newly-streamlined Marouane Fellaini's deft control and finish in the closing moments.
Sunderland and Bolton were sucked back towards the battle at the bottom after disappointing home defeats at the hands of Wigan and Fulham, respectively.
Black Cats boss Ricky Sbragia admitted his side had produced the worst performance of his tenure against the Latics, with former Newcastle winger Charles N'Zogbia silencing the Stadium of Light taunts with a superb solo winner.
Fulham claimed their first success on their travels this season and doubled their tally of goals away from Craven Cottage at a single stroke with Andy Johnson, Simon Davies and Diomansy Kamara putting Bolton to the sword.
Four points separate first to third and fourth to sixth, with 12th to 18th covered by a similar margin. Twists, turns and tension are guaranteed over the final nine games of the season.