Pompey had to bide their time before finally breaking the resistance of the League One leaders.
They created the better chances of a scrappy first half, but it was after the break that they got the job done against Wycombe at a damp Fratton Park.
Ben Close followed up to score after Ellis Harrison had struck the post, while Ronan Curtis converted Marcus Harness’ cross to make the points safe.
And Kenny Jackett was pleased with the way his side stuck to the task and continued their fine home form.
The Blues boss said: “It was a hard-fought game and Wycombe are a tough nut to crack – you can see why they’re top of the table.
“It was never going to be easy for us against a terrific unit who make life difficult for you all over the pitch.
"There were some good bits of finishing from our players and those moments of composure really made the difference."
“Gareth Ainsworth has done a fantastic job there, but I’m pleased to say that they key moments went our way.
“There were some good bits of finishing from our players and those moments of composure really made the difference.
“We had to persevere and stick with it, creating some really big chances at the start of the second half, like the header from James Bolton.
“There was that neat side-step from Ben that got us up and running. I’m really pleased for him because he’s chipped in with some key goals.
“Ronan’s one gave us a little bit of breathing space and when he combines with Ellis, they look a real partnership.
“We have to keep sticking with that because we feel it can keep improving and make a real impact for us.”