Kane scored three minutes after the break, following Dele Alli's first-half opener, to give on-looking England boss Gareth Southgate plenty to smile about and also strengthen his side's top-four aspirations.
16': Dele Alli (Tottenham Hotspur) right footed shot from the centre of the box to the centre of the goal. Assisted by Christian Eriksen.
26': Andre Gray (Watford) right footed shot from the centre of the box is saved in the centre of the goal. Assisted by Etienne Capoue.
48': Harry Kane (Tottenham Hotspur) right footed shot from the centre of the box to the bottom left corner. Assisted by Kieran Trippier.
68': Jan Vertonghen (Tottenham Hotspur) hits the right post with a header from the centre of the box. Assisted by Kieran Trippier with a cross following a set piece situation.
70': Richarlison (Watford) right footed shot from the centre of the box is too high.
90': Moussa Sissoko (Tottenham Hotspur) right footed shot from the centre of the box is close, but misses the top right corner. Assisted by Harry Kane with a through ball.