Goals from Dele Alli and Harry Kane, who marked his 150th Premier League appearance by finding the net, ensured a routine victory for Spurs, but they were unconvincing for long periods.
A pair of first-half saves from captain Lloris prevented Watford from equalising following Alli's opener, Andre Gray and Richarlison denied by the France international.
And Pochettino told Sky Sports : "I think it was a good night for us. It was important to get the three points as it allows us to be in a good position.
"It was a must-win game - so important for us. Perhaps we did not play in the way we wanted but got three points.
"During the whole season, 10 months, it is hard to keep playing good football. Watford are a difficult opponent, they played well, created great chances.
"Hugo Lloris was fantastic and showed why he is one of the best in the world. I am happy, three points puts us in a good position."
"The team came back from a difficult loss. They were disappointed after Manchester United," Pochettino added. "Watford were free to play, no pressure, they are safe, for us it is a massive pressure to take three points.
"Three games ahead, I think we are in a good situation. To win the games and finish in the top four for the first time [consecutively] would be great for the club."
Kane is now just four goals behind Liverpool's Mohamed Salah in the race for the golden boot, his effort taking him on to 27 in the league this campaign.
Speaking to Sky Sports, he said: "I feel good. I'd like to have played better in the last few games, same as the team, but I feel good, feel sharp and could have scored more. Hopefully I can finish strong like I did last season going into a big summer.
"I try to improve every year. Last year I got 29 goals so I'd like to beat that but we'll see what happens. In my mind I'm trying to get to that 30 mark."