Goals from Tokelo Rantie, Brett Pitman and Harry Arter capped an impressive first half as Cherries deservedly reached the interval 3-0 ahead at Fratton Park.
And although Howe’s men maintained the momentum into the second half, a stunning strike from James Dunne and Jed Wallace’s penalty saw Pompey claw back two late goals.
Howe said: “I was really pleased with the first 55-60 minutes and disappointed with the ending. But I thought we showed our qualities early on and looked a very good side.
“We changed the formation in the second half and tried to hit the players with something different. We didn’t adapt well enough but there is still time to get rid of those mistakes.
“We looked good for the first hour. We passed and moved the ball well, as we do, and looked like we had a cutting edge. We scored some good goals and I was pleased. I wanted us to make it five, six or seven by being really ruthless and professional.
“Unfortunately, we allowed them back into the game and made it difficult for ourselves in the last part. We defended our goal well when it went to 3-2 and saw out the game in the end.”
Howe, whose starting line-up included six players who had featured for only 20 minutes against Southampton, will see Cherries complete their friendly campaign with two games in two days – at home to Swansea on Friday and away to Oxford on Saturday.
He added: “We managed to give a couple more players some good game time and I felt that was important. We have two more games and that will be our last chance to get some proper game minutes into the players and I think we will be ready for the Huddersfield game.
“We will mix the teams and try to get positive results in both games. More importantly, the players will hopefully get that bit closer to feeling like they are ready to play.”
Howe said he hoped goalkeepers Lee Camp and Darryl Flahavan would recover from their respective injuries in time for Cherries’ Championship curtain-raiser at Huddersfield a week on Saturday.