Runaway Premier League leaders Manchester City opened up an eye-watering double-digit lead over rivals Manchester United after Nicolas Otamendi fired Pep Guardiola's men to derby victory.
The much-anticipated 175th Manchester derby was comfortably the biggest game of the Premier League season, such was the need for Jose Mourinho's Reds to claw back their swashbuckling rivals.
But the gap between table-topping City and second-placed United grew to 11 points on Sunday as City triumphed 2-1 at Old Trafford, where Otamendi volleyed home a second-half winner after Marcus Rashford had cancelled out David Silva's opener.
The untimely end to United's club record-equalling 40-match unbeaten home run strengthens their rivals' grip on the title after just 16 matches - of which they have won the last 14 in a row.
That is a new top-flight record run within the same season and an outcome that looked likely after Silva gave City a deserved first-half lead, with the playmaker capitalising on a corner that had deflected off Romelu Lukaku.
United fortuitously went into the break level after Rashford capitalised on a Fabian Delph mistake, but the blue half of the city were not to be denied as Lukaku's hashed clearance allowed Otamendi to volley home early in the second half.
Ander Herrera was booked for diving in the box and Ederson Moraes produced an outstanding double save as the hosts tried to snatch a draw, but City move onto 46 points as a result of a victory that leaves Mourinho's men reeling.
Player ratings
Manchester City made it a Premier League record 14 successive wins in the same campaign with victory over fierce rivals Manchester United at Old Trafford.
David Silva fired the Blues ahead late in the first half, but some lackadaisical defending allowed Marcus Rashford to strike in stoppage time before the break.
But Nicolas Otamendi sealed the points in the second period, scoring his fifth goal in his last 15 appearances from close range after a mistake by Romelu Lukaku.
Silva caught the eye of our man David McDonnell, but who was your man of the match on derby day in Manchester?
Here are the full player ratings...
Five talking points
Manchester City delivered a hammer blow to Manchester United’s title chances with a 2-1 win at Old Trafford.
The victory sees Pep Gaurdiola’s men move 11 points clear of their neighbours in the Premier League, as David Silva and Nicolas Otamendi capitalised on two errors from Romelu Lukaku, either side of a Marcus Rashford strike.
The visitors dominated possession in the opening exchanges, but were unable to truly test David De Gea until David Silva slotted home after Romelu Lukaku’s misplaced chest down fell to the City winger at a corner.
City appeared to be heading to a half-time lead, but errors from Nicolas Otamendi and Fabian Delph let Marcus Rashford level the scores.
It was deja vu all over again ten minutes unto the second half for the hosts though, as Lukaku notched up another City assist, when his clearance from a Silva free kick in the six-yard box cannoned into Ander Herrera and fell to Otamendi, who put City ahead again.
Here are five talking points from Old Trafford...
GOAL! Manchester United 1-2 Manchester City (Otamendi)
City back ahead!
Otamendi is in fine goalscoring form, and he has another, with a huge help from Lukaku.
Silva floats in the free kick, it seems an easy clearance for Lukaku but he smashes is into his own man, and Otamendi finishes smartly from close range.
His fifth goal in his last 15 appearances.
City lead 2-1.
GOAL! Manchester United 1-1 Manchester City (Rashford)
United hit back immediately!
A shocker from Otamendi and Delph - the centre-half completely misses his header and Delph fails to clear allowing Rashford to have a free run at goal, and he makes no mistake past Ederson.
I’m not sure how - but United are going to go in at the break level.
1-1!
GOAL! Manchester United 0-1 Manchester City (Silva)
Silva gives City the lead!
It’s been fully deserved for the visitors.
De Bruyne swings over the corner, it ricochets off Lukaku and Silva hooks home from close range.
City have dominated and hopefully that goal will open things up somewhat.
0-1!
Man City team
Man City: Ederson, Walker, Otamendi, Kompany, Delph, De Bruyne Fernandinho, Silva, Sterling, Gabriel Jesus, Sane.
Subs: Bravo Danilo, Gundogan, Aguero, Mangala, Bernardo Silva Alexander Zinchenko.
Man United team
Man United: de Gea, Valencia, Smalling, Rojo, Young Ander Herrera, Matic, Martial, Lingard, Rashford, Lukaku.
Subs: Lindelof, Jones, Mata, Ibrahimovic, Romero, Shaw, McTominay.
Matic lauds Mourinho effect
Nemanja Matic has spoken ahead of the derby about how Jose Mourinho’s relentless drive and winning mentality has infected the Manchester United squad. Old Trafford plays host to the biggest match of the Premier League campaign when swashbuckling Premier League table-toppers Manchester City arrive on Sunday afternoon.
Pep Guardiola’s runaway leaders boast an eight-point match heading into the 175th Manchester derby, making it crucial for Mourinho’s men that they do not slip any further behind.
United are buoyed by a run of four straight Premier League victories, displaying the kind of winning mentality that Mourinho has instilled in a club that had lost their way after Sir Alex Ferguson’s retirement.
“Yeah, he’s a manager who has won many trophies and he always wants to win,” summer signing Matic said. “When you’re in a club like Manchester United and when you have Jose Mourinho as manager, you always want do more and always want to win. “I understand that from him and I’m sure we will do our best to earn some more silverware this season.”