Sebastian Prodl has described Richarlison as one of Watford's "key players" and has backed the Brazilian to rediscover his early-season form.
The 20-year-old arrived from Fluminense in August midway through the Brazilian season and scored three goals in the opening seven games for the Hornets.
Richarlison's form has since tailed off, the youngster failing to score in his previous 11 games.
Prodl, however, has come out in support of his teammate and has urged fans to give the forward more time.
"He had an impressive start to his first Premier League season, of course, but we have to know he came straight from Brazil, he didn't have a long break in summer," Prodl told Sky Sports News.
"Also he is still a young player, [there will be] some games where he is not on top, he is a top player, he's always putting problems to the opponents so that's why they mark him even better now and also he might have a little struggle with tiredness.
"But he is one of our key players, we need him and he will get back on track, he will score, he will assist again. That's what we expect from him and that's what he expects from himself as well."
Watford have slipped to 10th in the Premier League table after losing four of their last five games.