Claudio Ranieri says he needs to choose players that want to "fight hard for Watford" after a damaging defeat against Norwich saw them drop into the Premier League relegation zone.
Norwich picked up a 3-0 win to move out of the bottom three for the first time this season and send Watford into it.
The Hornets have suffered 11 defeats in 13 games under Italian Ranieri.
"It's very important the lesson Norwich gave us, they played as a team, we played as individuals," said Ranieri.
The 70-year-old veteran was furious with his players after a result that sees them fall to 18th place following a run of seven defeats and one draw in their past eight games.