The Hornets' 1-0 win over Swansea City last weekend all but secured their top-flight status for another season, with 12 points now separating them from the relegation zone and only six games of the campaign remaining.
Watford will travel to Hull City on Saturday looking to tighten their grip on a place in the top half, but Mazzarri is wary of his side taking their foot off the pedal when they face the struggling Tigers.
"It is not easy to motivate the players after the win on Saturday, they might feel safe. I hope to manage to get into their heads everything that we have spoken about in the week [during training]," he told reporters.
"I was a player once, unfortunately, subconsciously, if you reach your target you relax, so I am curious to see what is going to happen when we play on Saturday. There are concepts that I have tried to instill since I first got here - that players give the best every match, don't look at the table.
"Now, we have got six finals and they need to give the best and also in these six matches I will see who's going to stay next season. They won against important teams; Bournemouth, Liverpool, West Ham and Swansea. If we look at the home record and the points they have at home they are in a good way."
Mazzarri also insisted that he will not leave the club this summer despite speculation over his future.