Kane’s goal also marked his 100th home goal for Spurs and made him the leading scorer in the north London derby.
He perfectly controlled a Moussa Sissoko pass from a Spurs counter-attack before setting Son off down the left side of the pitch.
Instead of attempting a darting run behind the Arsenal defence, Son unleashed the ball 20 yards out and it went soaring past Bernd Leno in the Arsenal goal.
A minute into extra time at the end of the first-half, it was then Son’s turn to provide an assist for Kane.
With Arsenal caught on the counter-attack again, Son held the ball until Kane appeared on his outside left and then slipped a pass to him. Kane then powered the ball into the roof of the net from close range.
Partey had limped off the pitch during the second Spurs counter-attack, leaving Arsenal a man down when Kane scored.
Despite enjoying the majority of the possession in the second-half, they were unable to find a goal as Spurs were happy to play defence after their first-half display.