Recent games on the road have seen Pompey dropping points in agonising fashion by conceding in stoppage-time.
So Kenny Jackett wants to see his side rediscover the ability to see matches out, something that happened on plenty of occasions last term.
The next opportunity arrives on Saturday afternoon, when a high-flying Oxford side visit the south coast.
Pompey are looking to preserve an unbeaten League One home record and Jackett is hoping for an assured performance.
The Blues boss said: “We’ve had spells in games where we’ve done good things, but it hasn’t all come together on a consistent basis.
“That’s the bottom line – and last week at Bristol Rovers was a prime example of that. There was a lot of quality, but we got one point when it should have been three.
“There’s been a few occasions when we’ve been in an encouraging position and haven’t got ourselves over the line, so that’s something that has to improve if we want to climb the table.
"We need to pick up points over a regular period, rather than just here or there."
“It’s one of the differences between now and what happened last season, but it’s certainly an area where we can do better.
“Confidence is absolutely massive in any football team and you're looking to earn that backing from the home supporters, but you’ll only get it with good performances and results.
“We need to pick up points over a regular period, rather than just here or there, but it would be great if we could get that ‘marquee’ win and the sooner, the better.”
Oxford are sitting fifth in League One and have booked their place in the quarter-finals of the Carabao Cup.
Jackett said: “We’ve had a very good week in training and I’ve been pleased with the attitude and response of the players.
“Now we’re looking to transmit that into Saturday’s game, which starts a big period for us with a lot of home matches.
“Oxford have climbed the table well after some troubles last season and have progressed in the cup as well.
“They’re a buoyant side at the moment and I’m sure it’s going to be a cracking contest – one we’re certainly looking forward to.”