Fortress Vicarage Road could prove the decisive factor if Watford make it back to the Premier League.
This was their 12th win from 16 home games this season - more than anyone else in the Championship - and it lifted them level on points with Brentford in the second automatic promotion place.
Joao Pedro and Will Hughes launched the quick one-two to sink Wayne Rooney’s Derby, ending their recent upturn in results that had eased relegation fears.
The Rams were second best here despite being gifted a late goal back and with their long-awaited Abu Dhabi takeover stalled, it’s proving difficult to shake off the anxieties that have plagued their season.