Two goals after the break saw Portsmouth continue their good home form against Watford this afternoon.
Hungarian centre-forward Marko Futacs broke the deadlock at Fratton Park in the 54th minute when he headed in a cross from Liam Lawrence.
The points were sealed three minutes from time when Hayden Mullins converted another cross from Lawrence.
The results means that Pompey are now unbeaten in their last seven home matches.