The Hornets got off the mark with all three points in their first Premier League match of the campaign thanks to a couple of goals from Roberto Pereyra.
Brighton, who finished a point lower than Watford last season, ended Saturday afternoon's match at Vicarage Road without a single shot on target.
Speaking to Sky Sports News after the match, Gracia hailed his side's performance and also talked up the quality of Pereyra's volleyed opener 35 minutes in.
"We had to start well, and with the support of our fans it is easier," he said. "I'm sure all the players make an effort to get good results. I'm very happy with the result, but happier with the way we got it. I think we played very good game, dominated all the game.
"They didn't have any shots on target or create any chances. The team showed a good reaction after losing the ball and I am very happy for them.
"I think today we have played the same way like our last game against Sampdoria in pre-season - very aggressive, good attitude and ambition. I'm very proud of my players.
"The goal? We tried to do it many times, it did not always finish the same way! We prepare different set pieces. We scored one goal similar with Kiko Femenia here last season and today I know Roberto has a high quality and he can do it."
Watford are now unbeaten in their last 12 opening games to a league season, with their last defeat coming against Everton in August 2006.