Dele Alli's double drove Tottenham to a first Stamford Bridge win over Chelsea since 1990 and left the Blues' Champions League qualification bid in tatters.
England star Alli's goals and Christian Eriksen's stunning long-range strike handed Spurs the 3-1 win - and an eight-point Premier League advantage over their fierce London rivals with just seven matches to play.
Chelsea's first home defeat to Tottenham in 31 matches in all competitions also turned the focus towards the future of manager Antonio Conte.
The Chelsea board may not be willing to accept failure to qualify for the Champions League from Conte, who led the west Londoners to the Premier League title just last term.