Roy Hodgson said there is still "a long way to go" this season despite claiming his first win as Watford manager.
Aston Villa dominated but Watford grabbed all three points when Emmanuel Dennis powered home Ismaila Sarr's 78th-minute cross after an opportunistic counter-attack.
It ended the visitors' four-game goal drought and lifted them up to 18th in the Premier League, four points from safety.
"The danger now is that we think we've cracked it and that what we needed to do between now and the end of the season has been done," Hodgson told BBC Match of the Day. "There's such a long way to go."
The managerial merry-go-round has been well reported, and Hodgson already seemed under pressure coming into this fixture after collecting just one point from an available nine since taking charge in January.
As the game went on, Watford were on course to drop to the bottom of the table and looked set to equal a club record of five consecutive games without a goal.
"We're going to need strong performances," said Hodgson.
"[We need] people who are prepared to chase back a bit more than they're used to doing. [We need people] to put their foot into challenges a bit more than they're used to doing."
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