Colby Bishop scored the decisive goal as Portsmouth clinched a 1-0 victory over 10-man Watford, securing their safety in the Sky Bet Championship.
Portsmouth are now six points clear from the relegation zone with just two matches remaining. With Hull and Derby set to face each other, Pompey's position in the league is assured.
The only goal of the game came in the 25th minute when Bishop headed home from close range after Egil Selvik parried Josh Murphy's cross. Watford's Kevin Keben was shown a red card in the 57th minute for a foul on Murphy just outside the box.
Despite a bright start from Portsmouth, it was Watford's Tom Dele-Bashiru who missed a good opportunity in the 17th minute, shooting straight at Nicolas Schmid.
Bishop had a chance to double the lead but was denied by Selvik, who was busy making saves throughout the match. Portsmouth's Matt Ritchie and Watford's Imran Louza also tested the goalkeepers with long-range efforts.
Watford tried to get back into the game, but their hopes faded after Keben's dismissal for a foul on Murphy. Portsmouth had further opportunities to score but were unable to convert.
The injuries to Bishop and Murphy are a concern for Portsmouth's manager John Mousinho ahead of the remaining fixtures, but the team's fighting spirit was evident as they secured their place in the Championship.