The Hornets stung Spurs on Sunday, coming from a goal down to claim their first Premier League win over the north London club.
A close run affair brought little highlights in the opening period, as Tottenham tried to break down a stubborn Watford defence. A bit of luck got Spurs in front as a Lucas Moura cross deflected off Abdoulaye Doucouré and past Ben Foster.
Watford rallied in the last 20 minutes, levelling through captain Troy Deeney, who nodded in a set piece. Tottenham seemed flustered with Watford's sudden resurgence as they quickly found themselves behind when Craig Cathcart was first to a well delivered corner.
Here's four things we learned from Sunday's game:
4. Troy Deeney Encompasses Hornets Spirit
Watford's leader once again proved vital in Sunday's contest as a spirited fightback turned the game on its head.
This was - in large part - thanks to Troy Deeney, who lead exceptionally from the front. The 30-year-old striker's physicality and work rate optimises the heart of Watford, which never let up for the entirety of Sunday's game.
Not only did Deeney level the game with a perfectly timed header, but his all round game got the home crowd off their feet and set the tone for the rest of his teammates to follow.
3. A Quiet Day for Kane
Like Deeney, Harry Kane usually is at the heart of all of Spurs success, but on Sunday he had a rare off day.
Struggling to find much joy against the centre back pairing of Christian Kabasele and Craig Cathcart, Kane was forced to drop deeper, looking for the ball. Seeming to always force an opportunity, the forward was left a spectator as his side struggled.
The one chance that did fall his way late in the game, sailed over the bar; solidifying a poor outing.
2. Spurs Summer of Inaction Proving Costly
Most of Spurs fans summer fears would've been put the bed after seeing their side claim victory in the opening three games; most notably triumphing at Old Trafford.
However, the lack of options off the bench when the game turned on Sunday is something that will concern Mauricio Pochettino. It's not a new problem for the Spurs boss, whose backup options have always been accused of lacking the quality needed to effect games.
Tottenham's lack of spending to challenge a strong first XI could prove a fatal mistake if results like this continue.
1. Watford Will Prove Tricky Customers for Top Teams
For Javi Gracia, he has now overseen wins against Chelsea and Tottenham at Vicarage Road, which will make Watford a difficult test for fellow top six sides.
Watford's start to the season shouldn't be underplayed. Plagued with defensive mishaps, lack of goals and little form at the back end of last season would've worried Watford fans for the upcoming campaign.
Now with their blend of physicality, commitment and flair in the likes of Roberto Pereyra, Watford can stun a few this season. If the opening four games are anything to go by, the Hornets could be in for a surprisingly great campaign.