Enzo Maresca’s team almost broke the deadlock inside the opening minute when Trevoh Chalobah looked to pick out Nicolas Jackson, who almost benefitted from Micky van de Ven’s interception ricocheting off him before cannoning off the post.
Tottenham were looking shaky at the back, and they were nearly punished after Marc Cucurella’s pass went straight through to Malo Gusto, whose effort hit the side netting.
The Tottenham backline were continuing to endure a torrid time, with Jackson firing over the bar after being given the freedom of the penalty box. Guglielmo Vicario was hardly looking convincing between the sticks for Spurs, but the Italian made a fine save to parry over Jadon Sancho's cross after the Manchester United loanee was picked out by Pedro Neto.
Ultimately, a lack of cutting edge from the hosts in the final third ensured both teams ended the first half on level terms.
Chelsea’s deserved breakthrough came in the 50th minute courtesy of Enzo Fernández, who powered home a header from Cole Palmer’s enticing cross to finally make the visitors pay for their hazardous defending.
The floodgates looked to have opened when Moisés Caicedo rifled home a superb volley after the visiting defence failed to deal with a Fernández set piece, but their blushes were spared as a lengthy VAR review determined an offside in the build-up.
The north Londoners then thought they had found an equaliser out of nowhere when Pape Matar Sarr’s speculative strike squirmed past Robert Sánchez.
However, VAR took centre stage once again, penalising the Senegal international for a foul on Caicedo. Postecoglou’s men were offering very little going forward, yet they could have claimed a stunning equaliser late on when Sánchez kept out Son Heung-min’s sliding attempt at the far post from Brennan Johnson’s cross.
It was hardly a classic to match the thoroughly entertaining clashes these two sides have served up over the years – not that Chelsea will care, claiming a 10th win in 13 PL meetings with their rivals from north of the River Thames.
Meanwhile, this marks a ninth away PL defeat of the season for Tottenham, with only Leicester City (11) and Southampton (12) losing more times on the road, leaving them languishing in 14th.
Flashscore Man of the Match: Cole Palmer (Chelsea)