Deeney scored twice for Watford in their 3-2 victory over Villa at home in the Premier League at the weekend.
The 27-year-old striker found the net twice in quick succession late on at Vicarage Road to help the Hornets pick up all three points from the encounter.
“It’s an exceptionally good striker who scored the goals,” Black told The Birmingham Mail. “He is an outstanding striker, who given the slightest opportunity scores.”
Against Villa at Vicarage Road on Saturday afternoon, Deeney took six shots, had a pass accuracy of 55%, created one chance, attempted one dribble, won 50% of his tackles and 75% of his headers, and made one clearance.
The Englishman has played well for Watford this season and has been key in them staving off relegation to the Championship.
Deeney has scored 11 goals and created 52 chances in 35 Premier League appearances for Watford this campaign.
The striker has a pass accuracy of 60% and a shot accuracy of 49%, and has won 212 headers, 20 dribbles and 34 tackles.