The Lilywhites, reduced to 10 men for the final 38 minutes after Davinson Sanchez was dismissed, have now taken just two points from the last 12 on offer since the international break.
Christian Kabasele had edged the hosts ahead 13 minutes into the match in Hertfordshire, before Son Heung-min levelled up to at least deny the Hornets a first ever Premier League victory in this fixture.
The home side took some time to get going, but they soon found their flow and found themselves ahead when Kabasele climbed highest to meet Richarlison's corner.
Spurs levelled up from the next big chance of the contest, though, with Christian Eriksen providing Son with the easiest of finishes from close range after the visitors hit their opponents on the counter.
The Hornets were made even angrier due to a perceived block by Ben Davies on Richarlison in the build-up to the goal, and from that point on out-of-form Spurs looked the more likely to add a second.
A pivotal moment in the match arrived seven minutes into the second half, however, when referee Martin Atkinson reached into his back pocket to shown Sanchez a red card after he blocked off the run of Richarlison on the break.
Despite being reduced to 10 men, Spurs were still looking to find a winner in a match that could have gone either way, but Watford came closest to snatching the points when Abdoulaye Doucoure's shot from 30 yards came back off the post.
A late penalty shout aside, with Eric Dier accused of handling the ball in the box, neither team managed to threaten in the remaining minutes as the points where shared.
Watford: Gomes; Prodl, Mariappa, Kabasele (Capoue 64'); Cleverley (Gray 88'), Doucoure, Femenia, Zeegelaar; Richarlison, Pereyra (Carrillo 67'); Deeney
Tottenham Hotspur: Lloris; Trippier, Vertonghen, Sanchez, Davies; Dier, Dembele; Dele (Winks 86'), Eriksen (Sissoko 64'), Son (Lamela 76'); Kane body check tags ::