Alvaro Morata’s 55th-minute header sealed a 1-0 win for Chelsea over Manchester United, who fell eight points behind league leaders Manchester City.
Morata, who revealed he had an offer to join United before signing for Chelsea this summer, headed home Cesar Azpilicueta’s cross (55) to ease the pressure on Antonio Conte.
With Manchester City beating Arsenal 3-1 earlier on Super Sunday, the title race has already taken a big swing to the blue side of Manchester but Chelsea closed to within nine points with this deserved victory.
The result means Jose Mourinho has not won any of his last 11 Premier League away games at the ‘big six’ with his teams failing to score in nine of the last 10 matches.
Mourinho’s team unexpectedly pressed high early on, with their full-backs playing like wingers at times.
This resulted in an end-to-end game played at a good tempo. Phil Jones thumped a left-wing cross into his own net but was deemed to have been fouled by Morata while Marcus Rashford looped a header over the crossbar when well placed.
Tiemoue Bakayoko then sliced wide with the goal gaping and Andreas Christensen headed over from seven yards out following a wonderful Cesc Fabregas corner.
Their next headed chance would not be wasted. With 55 minutes gone, Azpilicueta found space down the right and planted a sensational ball into Morata, who thumped a header into the top corner. It was the fifth time this season Azpilicueta had supplied an assist for the Chelsea striker.
Chelsea looked the more likely to grab the second goal with Bakayoko firing wide when clean through on goal before Eden Hazard forced a smart save from David de Gea.
With the clock running down, the withdrawal of Fabregas seemed to inspire United and substitute Marouane Fellaini was denied by a flying Thibaut Courtois save.
That proved to be the last chance as Manchester City head into the international break firmly in control of the Premier League.
Chelsea: Courtois (7), Azpilicueta (8), Christensen (6), Cahill (7), Zappacosta (6), Bakayoko (6), Fabregas (8), Alonso (6), Kante (7), Morata (8), Hazard (7)
Subs: Willian (6), Drinkwater (6), Rudiger (6)
Manchester United: De Gea (7), Bailly (6), Valencia (6), Jones (6), Smalling (6), Young (6), Herrera (6), Matic (6), Mkhitaryan (6), Lukaku (6), Rashford (6).
Subs: Fellaini (6), Martial (6)
Man of the match: Cesc Fabregas