Chelsea manager Maurizio Sarri has admitted his side have "a lot of problems" after suffering their first defeat of the season on Saturday.
Tottenham Hotspur produced an emphatic 3-1 win over their London rivals at Wembley Stadium, and despite the defeat, the scoreline flattered Chelsea.
England midfielder Dele Alli opened the scoring for Spurs, flicking on a Christian Eriksen set piece, before striker Harry Kane doubled his side's lead with speculative long-range effort.
South Korean forward Son Heung-Min completed the rout nine minutes into the second half, with French striker Olivier Giroud pulling one back for Chelsea with five minutes remaining.
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Spurs, who for years seemed doomed to lose to their cross-town rivals, produced their best performance of the season as the muscular midfield pairing of Mousa Dembele and Eric Dier led a high-pressure harassment of the visitors.
Chelsea, by contrast, were their worst since Sarri took over as manager this year and they meekly surrendered their 12-match unbeaten Premier League run under the Italian.
Spurs leap-frogged Chelsea into third place in the table and Arsenal will be only one point behind Chelsea in the fourth Uefa Champions League spot if they beat Bournemouth on Sunday.
Spurs showed more urgency from the kick-off, snuffing out Chelsea's Italian playmaker Jorginho and Belgium forward Eden Hazard.
The final score could have been much worse for Chelsea had it not been for a string of saves by Kepa Arrizabalaga and wasteful Spurs finishing.
Sarri had warned before the game that Chelsea's strong start to the season risked running out of steam, in large part because of the unfocused way they began matches.
"I knew very well that we had a lot of problems to solve and I think that today was clear for everybody," he told reporters.
"I told [the players] in the last two weeks that we had a big problem with the approach to the match and today we had the same problem."
Sarri lamented the "disaster" of his side's defensive work and Chelsea were just as ineffective in attack, forcing the manager to substitute out-of-form striker Alvaro Morata and play Hazard as the focal point of a forlorn attack.
Spurs manager Mauricio Pochettino said he wanted the win to serve as a template for the rest of the season.
"The attitude and the will were fantastic," the Argentine said. "The challenge now is to keep that level of competition ... We need to realise that with the right attitude we are team that can compete at this level."