It was not too long ago that Pompey were able to boast the best scoring record in League One.
But the goals have been harder to come by in recent weeks, with just three netted in the past four games.
The most recent came in a 1-1 draw with Gillingham on home soil, as Sean Raggett’s header was cancelled out by Vadaine Oliver.
And Tom Naylor knows the Blues have to be more clinical in order to improve their record at Fratton Park.
Pompey’s skipper said: “It was a tough game, but we knew it would be a battle. We had chances in the first half, though, and their keeper made some great saves.
“We got in front with a really good goal and we then went off it a bit and their goal was from a mistake.
"That’s the bottom line. We haven’t been good enough at Fratton Park all season and it has to change."
“It feels like when we’re scoring at the moment, we’re not applying enough pressure to go 2-0 or 3-0 up.
“We’re in a difficult period and after a really professional and solid performance on Tuesday, we knew we had to win at home.
“That’s the bottom line. We haven’t been good enough at Fratton Park all season and it has to change.
“We do miss the fans massively – especially when we’re going towards them after the break. They’re our 12th man.”
Naylor had to receive treatment on the pitch after hurting his back and hip following a challenge in the first half.
He said: “I was struggling because it was really sore, but adrenaline got me through the rest of the game. I’ll see how it is, but I should be alright for Tuesday.”