Kevin De Bruyne, Sergio Aguero and Gabriel Jesus were on target as Manchester City underpinned their status as Premier League title favourites with a dominant 3-1 beating of an outclassed Arsenal.
Belgium international De Bruyne continued a sublime season by beating Petr Cech with a well-placed shot during a first half completely controlled by the home side at the Etihad Stadium.
Aguero, who became City’s all-time club-record goalscorer in the 4-2 Champions League beating of Napoli, then completed a memorable week with City’s second from the penalty spot early in the second half.
Substitute Alexandre Lacazette briefly restored hope for Arsenal, but Jesus – who also came off the bench – ended hope of what would have been an unfair comeback.
It was a more-than-deserved three points for City, whose mesmeric play, lightning speed and swift movement left Arsenal with no reply, and in truth the scoreline could have been worse had Aguero not missed an early chance and Sterling showed more composure in a two-on-one.
City, who had beaten Arsenal just once in nine competitive matches prior to the fixture, have now stretched their unbeaten run to 23 matches and lead the Premier League by eight points from Manchester United.
In another derby at Stamford Bridge, Morata’s 55 minutes header provided the lone goal that separated Chelsea from Manchester United.
Manchester United looked desperately out of sorts as Chelsea claimed a deserved 1-0 win thanks to Alvaro Morata’s header at Stamford Bridge.
The Spanish striker was reportedly close to a move to Jose Mourinho’s side before his eventual switch to the Blues and he haunted United with the game’s decisive moment in the 55th minute.
The former Real Madrid man escaped the attentions of United’s three central defenders – Eric Bailly, Chris Smalling and Phil Jones – to meet Cesar Azpilicueta’s cross with an immaculate header and secured all three points for Antonio Conte’s side.
United looked bright in the opening 20 minutes – coming close through Marcus Rashford’s looping header – but faded badly and posed little threat during a desperately poor second-half display.
The defeat means they are now eight points behind Premier League leaders Manchester City, whose seemingly unstoppable march at the summit continued with a comprehensive 3-1 win over Arsenal earlier on Sunday.
Chelsea, who have now lost just once to United at Stamford Bridge in 16 league games, remain in fourth place, but are just a point behind their beaten opponents and Tottenham