Domingos Quina, Troy Deeney, Nathaniel Chalobah and Joao Pedro scored for the Hornets, with Tom Barkhuizen finding the net for PNE.
Here's how the players fared on the day...
1. Declan Rudd - 6
Pulled off some good saves throughout the game and has been consistent of late, could do very little with any of the goals. Guessed right for the penalty but done for pace.
2. Jordan Storey - 6
Not his best game but had a tough task to keep Watford's talent quiet. His man got away from him for the first goal but he's still young and should learn.
3. Patrick Bauer - 6
Like Storey, can do better. Had one of PNE's best chances up the other end, firing from a tight angle (above) but seeing it smothered by Foster.
4. Ben Davies - 7
Showed his class on his return to the side, so calm and composed with great pace too. Showed why PNE miss him out of the team.