The Hornets are unbeaten after four Premier League outings, having won two and drawn two, and they currently sit fourth.
Watford have quietly gone about their business in the early stages of the term under new boss Marco Silva and Doucoure believes a top half-finish is certainly achievable, although he insists they are just taking it one game at a time.
"It's too early to talk about it," Doucoure said.
"We have to stay in the Premier League first and I think the top 10 is possible for us.
"It's too early to talk about that and we [will] take it game-by-game."
Silva’s men will face arguably their toughest test of the campaign this weekend when they welcome Manchester City to Vicarage Road, but Doucoure insists Watford believe they can cause an upset.
He added: "You can win every game but Manchester City are a very strong team.
"We believe in our team.
"We're very good and we can get a good result against City. We just have to believe and work like we did at Southampton - after [that] anything can happen."