The Hornets chief was naturally pleased with Sunday's 1-0 win at Middlesbrough which moved the side into mid-table in the Premier League with 11 points from eight matches.
However, while Mazzarri heaped praise on the defence for ensuring Boro were restricted to just one tame effort on target throughout the match, he felt the forward players could have done more to make their life easier at the Riverside Stadium.
The Italian told the London Evening Standard: "I was happy with our defensive performance but I want my team to create many more goal opportunities and to be more attacking. We were very good defensively but we’ve played better in other games."
Record signing Isaac Success, who was handed his first start for the club on Sunday, was the only attacker who was given praise by Mazzarri.
He added: "He's done well coming off the bench before, so it wasn't easy for him to come in from the start but he did well."