Portsmouth slipped to a club record ninth consecutive defeat at the hands of Bournemouth, who moved to within a point of the League One summit.
Adam Reed went close for Pompey while Patrick Agyemang, one of three debutants, headed wide from six yards.
But Lewis Grabban, who had earlier hit the crossbar with a header, swept in Josh McQuoid's pass for the Cherries.
Marc Pugh made sure of victory for his side when he latched on to Brett Pitman's pass and slotted home.
Portsmouth are now second from bottom, 11 points adrift of safety.
VIEWS FROM THE DRESSING ROOM
Bournemouth manager Eddie Howe told BBC Radio Solent:
"We prepared for it all week, we knew what type of game it would be, and full credit to Portsmouth because they came here with the game plan that we expected. Even though you know it's coming it's still difficult to conquer it and to break them down was difficult, I thought they defended really well."
On the build-up to the first goal: "I thought Josh [McQuoid] played a really big part in it, and then Grabbs [Lewis Grabban] had a lot of time to wait and to pick his spot but he's done that very well for us. A really important goal, that one."
On being on 55 points, one point off top spot: "That's good to know, good to hear. We're taking it a step at a time. It's a big victory today - it was the same three points available today as it was last week and everyone had us down as a home banker and that's never easy. We had a lot of pressure on us and I thought the players adapted very well to that."
Portsmouth caretaker manager Guy Whittingham told BBC Radio Solent:
"You're not pleased when you lose, but I'm pleased with the effort we put in and the discipline we showed the majority of the time.
"We just lost that little bit second half where we just started coming into the game and causing them some problems defensively.
"We went a little bit too far forward and lost our discipline at the back and got caught out.
"It's a huge achievement for us to be competitive at this moment in time. I think everybody's doing all they can and we need to keep doing that for our great fans."