Watford debutant Emmanuel Dennis opened the scoring for the Hornets as Aston Villa went down in their Premier League opener by 3-2.
The Nigerian forward followed up his own blocked shot when played in by Ismaila Sarr, who himself made it 2-0 before half-time after Dennis returned the favour with an assist and his effort was deflected in by Tyrone Mings.
Cucho Hernandez made it three with a brilliant strike just after the hour mark, only for John McGinn to make it 3-1 minutes later.
Ings scored a penalty deep into stoppage time when Bertrand Traore was tripped by Adam Masina, but it was too late for Villa who start life without Jack Grealish in an unflattering fashion.
Obviously, the absence of Grealish, who has now moved to Manchester City, was felt even though Emiliano Buendia and Danny Ings started as his replacement before Leon Bailey was introduced in the second half.