Zlatan Ibrahimovic scored an 84th-minute header as Manchester United prevented Liverpool from recapturing second place in the Premier League table in a 1-1 draw on Sunday.
Paul Pogba stood to be United's fall guy at Old Trafford after conceding a soft first-half penalty for handball, which James Milner converted, only for Ibrahimovic to save his blushes.
Ibrahimovic's 19th goal of the season extended United's unbeaten league run to seven games, but after winning the previous six, momentum has been lost.
Jose Mourinho's side remain sixth, four points off the Champions League places, while Liverpool rose one place to third, seven points below leaders Chelsea and beneath Tottenham Hotspur on goal difference.
After draws against Sunderland and Plymouth Argyle and a defeat at Southampton, Liverpool have gone four games without victory at the start of a calendar year for the first time since 1993.
But with United five points below them, Jurgen Klopp's men remain the more likely champions.
An abdominal injury to Nathaniel Clyne saw Liverpool's 18-year-old right-back Trent Alexander-Arnold given a full league debut and he had the onerous task of handling the livewire Anthony Martial.
Martial scored a memorable goal against Liverpool on his United debut last season and he fashioned the first opening with a deep cross for the leaping Ibrahimovic, who could only volley wide.
Ibrahimovic gave the visiting fans a heart-in-mouth moment when he chased down Dejan Lovren's weak back-pass, with Simon Mignolet's clearance striking him and looping onto the roof of the net.
United appeared to be taking control and in the 19th minute Henrikh Mkhitaryan bisected the Liverpool defence with a neatly judged pass for Pogba, only for the Frenchman to scuff wide with his left foot.
Liverpool's play had been more conspicuous for misplaced passes than anything else, but errors from Phil Jones and Pogba enabled them to take the lead in the 27th minute.
Jones's heavy touch allowed Roberto Firmino to rob him on the edge of the box, obliging Marcos Rojo to tidy up at the expense of a corner.
Pogba inexplicably leapt with his hands above his head as he defended Milner's set-piece and the Liverpool number seven tucked the ensuing spot-kick past David de Gea for his sixth penalty of the season.
United twice threatened an equaliser before half-time, Ibrahimovic blasting a free-kick towards the bottom-left corner and Mkhitaryan taking aim from Ander Herrera's pass, but Mignolet saved twice.
Mourinho took remedial action at the interval, sending on Wayne Rooney for his 450th league appearance and withdrawing Michael Carrick, with Herrera dropping into the holding role.
United spurned a great chance to equalise when, having robbed Alexander-Arnold on halfway, Martial sprinted into the box to meet Mkhitaryan's low cross, only to miscue his attempt at a back-heel.
But with Carrick off, United's back four was exposed to counter-attacks.
Divock Origi saw a shot deflected wide, a missed header by Jones allowed substitute Philippe Coutinho to slip in Firmino, obliging De Gea to block, and Georginio Wijnaldum headed Emre Can's cross over.
It was left to Ibrahimovic to ride to United's rescue, the Swede steering a fine header over Mignolet from Antonio Valencia's cross after Marouane Fellaini's header came back off the post.
The noise that Mourinho had called for after United's mid-week League Cup semi-final first-leg win over Hull City duly arrived, but Liverpool withstood the crescendo.
Manchester United 1-1 Liverpool: full time
Min 94 | That's it, final whistle at Old Trafford. Points shared.
Min 94 | Into the final minute as United press on. Great last 15 minutes of football at Old Trafford.
Min 93 | Wijnaldum free in space fires a tame shot straight at De Gea. Great chance for the away side to snatch all three points. Poor finish form the Dutch player.
Min 92 | 4 minutes of time to be added
Min 91 | Herrera pulls Firminho's shirt and is carded, the Brazilian retaliates by slapping the Basque player and is carded too for his action.
Min 90 | Mourinho bellows instructions at his side with the game into the last minute
Min 88 | Two United subs involved in the United goal with Rooney feeding the original ball for Fellaini.
Min 86 | Ibra bags the 600th Premier League of the 2016/17 campaign
Min 84 | The ball ricochets off the bar from a Fellaini header, the ball is fed back into the danger area from Valencia and Ibrahimovic glances the ball home with a header.
Min 84 | Ibra heads home ....Goooooolllll
Min 82 | Rooney almost bags goal 250 but Mingolet saves well. The linesman had his flag up so the goal would not have stood.
Min 81 | If anything Liverpool look like the likelier side to score next.
Min 79 | Time running out for United as we head into the final ten. The Red Devils lacking any creativity and the wall of lime green stands strong.
Min 76 | Wijnaldum latches onto a great cross only for Dutch player to fire the header over the bar. Fellaini on for Darmian.
Min 74 | Coutinho has looked bright since his introduction. Fellaini set to make way as Mourinho has one more change to make.
Min 72 | Brief hold up in play as Millner receives treatment to a knock.
Min 67 | Lallana strikes on target and forces De Gea to smother well from the right footed drive.
Change for United: Mata on Martial off
Min 65 | Ball falls to Rooney in space on the edge of the area but a poor strike from the United player.
Min 63 | Possession: 53/47%: United on top in terms of possession but it's the Reds from Liverpool with the all important goal.
Min 62 | Wijnaldum second name in the book tonight
Min 61 | Great link-up play from Coutinho and Firminho as Dea Gea is called into action to repel a right footed drive from the player who has just been brought into the action.
Change for Liverpool: Off Origo, on Coutinho.
Min 58 | Liverpool dealing well with the added United tempo and apart from the Mkhitaryan effort nothing to trouble Mingolet in the visitors goal. Juan mata to make an appearance.
Min 55 | Far more urgency surrounding United now and the home support doing their bit to rally the side after a very quiet first 45'.
Min 54 | Mkhitaryan through on goal at an acute angle and completely screws his shot wide when hitting the target would have been easier. A let-off for the away side there.
Min 52 | Old Trafford gets behind the team with chants of "Uni-ted, Uni-ted " ringing out
Min 50 | Rooney flashes a cross from the by-line but no red shirts are waiting in the box.
Min 48 | Origi fires a goal-bound shot that Jones manages to head wide. Early danger from the visitors.
Min 46 | Rooney for Carrick the only change at the break.
HT analysis: Tonight's game is better than when both sides last met at Anfield but is far from a classic. The men in lime green have shaded proceedings and are deservedly ahead after a unfortunate handball from Pogba which was well spotted by referee Michael Oliver. James Millner dispatched the spot kick and apart from a Mkhitaryan one on one and an Ibra free kick , United have rarely threatened the Liverpool goal.
That's it, whistle blows for the break at Old Trafford.
Min 45 | Last minute as Mou makes his way to the dressing room.
Min 43 | More pressure from the away side as a lofted cross hits the bar and earns the visitors a corner kick. The scoreline is a fair reflection of what we've seen in the first half.
Min 41 | Mkhitaryan breaks through, one on one with Mingolet and fires his shot straight at the Liverpool keeper. Decent half from the former Dortmund player.
Min 41 | Shots on target: United 1-1 Liverpool
Min 39 | Pressure from Liverpool as Origi tries his luck and runs out of space as the ball falls to Lallana who tries a right foot shot which is deflected.
Min 38 | Mourinho orders Wayne Rooney to warm up. HT sub maybe?
Min 37 | As things stand (obviously with a long way to go at Old Trafford) but Liverpool with a win are second in the table !
Min 35 | United looking for a way back into the game but but the lime green wall currently looking resolute
Min 33 | Ibra strikes and Mingolet does well to palm away
Min 32 | Herrera tripped on the edge of the area and United awarded a dangerous free kick.
Min 31 | Lovren booked, first caution of the evening
A brave call from match official Michael Oliver as he spots Pogba clearing the ball with his arm. Calm finish from Millner to see the visitors take the lead.
Min 27 | Millner takes and scores .............Goooooooooooooool
Min 26 | A Jones slip-up almost lets Liverpool as Lallana watches the ball roll out..... PENALTY for Liverpool !
Min 25 | Possession: 46/54%, Liverpool shading possession currently
Min 24 | The travelling Liverpool fans now making themselves drowning out the chants of the home fans.
Min 22 | Pogba clearly inspired by the Liverpool kit with a lime green tram-line in his hair tonight !
Min 19 | Pogba goes agonisingly close after picking up a delightful through ball from Mkhitaryan and just pulls his shot inches wide. Better stuff now....
Min 19 | United almost sneak a lead after Ibra latches on to a poor pass back to Mingolet and watches as the ball just goes over the bar.
Min 17 | The Spanish commentary team already making comparisons with the 16/17 season game at Anfield....Lightning can't strike twice surely ?
Min 14 | Ibra goes close as an over-hit cross from Martial is just too far from the Swede to get total contact on the shot and the ball hits the side netting.
Min 13 | Martial tumbles in the Liverpool area and the Old Trafford faithful scream for a penalty but the referee is not impressed.
Min 11 | I had the mis-fortune to cover the game between both sides at Anfield in October and can safely say that it's up there in the top 10 of "worst games of all time" that I've had to witness..tonight must be better ....
Min 9 | The game has yet to find a defined pattern with the play being interrupted by off sides and niggly fouls.
Min 5 | Better from United now as they start to string passes together and move the ball with purpose in the opposition half.
Min 3 | Bright start from the visitors as Origi wins an early corner for Klopp's side
Min 2 | The third worst kit of 2016 may be a bit harsh but the lime green third Liverpool kit from New Balance is not easy on the eye.
Min 1 | Liverpool get us underway...
A minute's applause now taking place at Old Trafford in memory of the late Graham Taylor.
9c currently in the Northern English city as Pogba offers a pre match prayer.
Time ticking down to the 1700 CET kick off. The biggest game in recent English football history about to get underway at a packed Old Trafford.
Liverpool set to feature their lime green third kit, recently voted third worst for the year 2016. United in classic red shirts, white shorts and black socks
Manchester United - Liverpool: buildup
16:35 | We'll have a minutes applause today at Old Trafford iahead of kick-off n memory of former England boss Graham Taylor who passed away during the week,
Manchester United - Liverpool: lineups
United XI: De Gea, Valencia, Jones, Rojo, Darmain, Carrock, Herrera, Martial, Pogba, Mkhitaryan, Ibra.
Liverpool XI: Mignolet, Alexander-Arnold, Lovren, Klavan, Milner, Henderson, Can, Wijnaldum, Lallana, Firmino, Origi
Manchester United - Liverpool: match preview
After the 0-0 bore draw at Anfield in October hopes are high for a more exciting game this evening at Old Trafford as United (6th) welcome Liverpool (4th) in arguably the biggest game traditionally in English football.
With Manchester City on a wobble following their earlier defeat in Liverpool against the blue side of the city, today's match provides an excellent opportunity for both Jose Mourinho and Jurgen Klopp to make a statement at the summit of the Premier League.