What you need to know:
- Mourinho characteristically stoked his rivalry with Guardiola pre-match by claiming Raheem Sterling would start despite withdrawing from England duty due to injury.
- Sterling was only fit enough for a place on the bench and by the time he and Phil Foden were summoned, the game was gone for City as they continued to play in front of Spurs without any penetration.
Tottenham displayed their Premier League title credentials as goals from Son Heung-min and Giovani Lo Celso exposed Manchester City's defensive frailties in a 2-0 win that took Jose Mourinho's men top of the table on Saturday.
Spurs have not won an English top-flight title in 60 years, but showed defensive resilience to frustrate City's domination of possession and their clinical counter-attacking was reminiscent of Mourinho's title-winning sides in two spells at Chelsea.
Victory moved Tottenham moved two points ahead of Chelsea, who they face next weekend at Stamford Bridge.
Defeat leaves City already eight points off the leaders, albeit with a game in hand, down in 10th with just three wins from their opening eight games.
Pep Guardiola ended speculation over his future by committing to a new contract as City boss until 2023 this week.
The Catalan has won eight league titles at Barcelona, Bayern Munich and City, but Guardiola now faces a challenge he has never had before in rebuilding a second title-winning side at the same club.
For the sixth consecutive league game City failed to score more than once with little sign of Guardiola's men rediscovering the cutting edge of the free-scoring sides that won back-to-back titles in 2017/18 and 2018/19.
Tottenham's title challenge will be fully tested with Arsenal, Liverpool and Leicester also to come before Christmas, but they could not have made a better start to that daunting run as City's defensive problems on the counter-attack were exposed again.
Spurs could not believe their luck after just five minutes when one simple ball over the top from Tanguy Ndombele caught Joao Cancelo sleeping and Son had the pace and precise finish under Ederson to register his sixth goal in 11 games against City.
The game then settled into the familiar pattern of now 24 clashes between Mourinho and Guardiola as Mourinho's men defended their lead deep and waited for the chance to counter again.
City could even have found themselves 2-0 down inside 14 minutes as Harry Kane tapped home Son's cross but had strayed offside.
The visitors had 66 percent of possession but struggled to break down the mass ranks of Spurs defence.
Gabriel Jesus inadvertently deflected Kevin De Bruyne's low shot wide before Jesus did tee up Aymeric Laporte to slot home, but the goal was ruled out for handball by the Brazilian after a VAR review.
Two more De Bruyne efforts were desperately blocked inside the Spurs box early in the second period before the hosts landed the knockout blow with another simple counter-attack.
Kane was afforded plenty of time and space to collect a loose ball in midfield and drive forward before feeding Lo Celso, who had barely been on the field a minute and with his first two touches, controlled and then slotted the ball low beyond the advancing Ederson.
Mourinho characteristically stoked his rivalry with Guardiola pre-match by claiming Raheem Sterling would start despite withdrawing from England duty due to injury.
Sterling was only fit enough for a place on the bench and by the time he and Phil Foden were summoned, the game was gone for City as they continued to play in front of Spurs without any penetration.