Watford are leading Brighton & Hove Albion after 45 minutes of Championship action.
The hosts had the first chance of the match with 10 minutes played, but Alexander Merkel drilled a shot a long way wide of Tomasz Kuszczak's goal.
Andrea Orlandi then flashed a shot across the face of goal, while Fernando Forestieri saw his effort from Troy Deeney's flick saved by Kuszczak.
Watford took the lead when Ikechi Anya found space in the box and slotted into the bottom corner.
Anya then had plenty of space down the left once again, advancing before drawing a save from Kuszczak with a long-range effort.
David Lopez fired wide after Manuel Almunia had cleared a Stephen Ward cross.
Orlandi's corner then picked out Matthew Upson, but the Albion defender was unable to direct his header on target.
Brighton substitute Kazenga LuaLua hammered a shot against the bar as the first half reached its conclusion.