The Hornets are currently placed 14th in the Premier League, 11 points clear of the relegation zone, and they have progressed to the semi-finals of the FA Cup.
Of the Hertfordshire club's return to top flight football under Quique Sanchez Flores, Cathcart said: "For teams that come up, the first thing they want to do is to stay in the Premier League and build from there.
"We probably haven't had the credit we deserve but that's just the way the season has been. Leicester have been unbelievable - the way they finished last year and have carried on this year.
"It's been a strange Premier League year; it's been more like the Championship the way each team has beaten each other.
"Hopefully we'll show towards the end of the season that we deserve to be in the Premier League next season and build on it."