The hosts were in front and were looking to extend their lead when Richarlison tumbled under a challenge from Davies inside the area.
Referee Martin Atkinson waved play on and Spurs broke in numbers. Eriksen rolled an inviting cross into the six-yard box for Son to tap in.
Son scores to make it Watford 1-1 Spurs #COYS
— The Spurs Web (@spurs_web) 2 December 2017
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