Following their 5-1 demolition of Cardiff City on Friday, the Hornets travel to Anfield to take on Jurgen Klopp's side who have won just one of their last four league matches.
During the last game between both teams at Anfield last March, Salah scored four goals as the Reds' ran out with an emphatic 5-0 win.
The Egyptian winger might have struggled recently to find the back of net having registered just a goal in his last five games but Gracia is leaving no stone unturned as he hopes for a different performance.
“I don’t know how many goals he [Salah] has scored in his last games but I remember in the last game we played against him he scored a lot of goals,” Gracia said, per BT Sport.
“Then we try to do our job better because we will need to keep a very good level to compete and have the option of getting some points.
“I try to learn from all the games, of course. Every game is different, the seasons are different and the players have different moments, I’m sure the next games will be different.
“But we have analysed the last games against them, this season and last season as well and we try to do better next time.
“When I play one game, I always want the three points. I never say before the game that I am happy with just one.”
Liverpool sit at the top of the Premier League table with 66 points from 27 games and Salah is responsible for 17 of their 59 league goals this season, a tally that makes him the joint top scorer with Manchester City's Sergio Aguero.