Pochettino was critical of his players' failure to hold on to the lead given to them by Abdoulaye Doucoure's 53rd-minute own goal.
Instead, Javi Gracia's side rallied and scored twice from set-pieces during a devastating eight-minute spell which saw Troy Deeney and Craig Cathcart head emphatically past stand-in goalkeeper Michel Vorm.
Pochettino said this was the sort of game that a contender for the league title must win if they are to live up to heightened expectations after the 3-0 win at Old Trafford.
From that point forward, Watford was on the front foot and nothing Mauricio Pochettino pulled off his incredibly thin bench made any difference.
While Tottenham's 100 per cent start to the season ended, Watford's continued and they join Liverpool and Chelsea as the only two sides to have won all four of their opening Premier League games this term. It's not going to be easy for the South Korean to come back into the squad with Lucas on this kind of form, and it looks like we're yet to see the best from the Spurs no. 27.
"Today, it's good to compare".
"It's hard for me to understand after four years of us being contenders. He helped me a lot on the pitch, because he has more experience than me", he said.
One player that has not reached anywhere near his best yet is centre-forward Harry Kane, despite the fact he's already got two goals under his belt.
"I was very, very disappointed and my message is you need to go there like a lion and try to score in every single action".
Offences that will be met with a Stage 1 warning include throwing or kicking objects, disrespectful gestures toward officials, provocative or inflammatory motions, gesturing for cards to be shown or the video assistant referee to be consulted, repeatedly leaving the technical area, entering an opponent's technical area and time wasting. "I think it's obvious that nothing gets us down", Kabasele added.
"That is why after the third game because we beat Manchester United and the circumstances that we beat them, we need to be more cautious. Knowing it's only the beginning four games, but we're enjoying this moment".