Pompey were surviving on their Fratton form in the opening part of the season.
But Kenny Jackett’s men are now starting to shine on the road – having won their past five away games in all competitions.
That includes Saturday’s 2-0 triumph at Tranmere, courtesy of goals from Sean Raggett and Ryan Williams.
It has helped boost hopes of securing promotion, although Jackett does not feel their performance levels have improved dramatically.
The Blues boss said: “We played well in certain games, but couldn’t quite get over the line in terms of the result.
“There were key mistakes, which aren’t acceptable, although sometimes the performance can be similar and yet the outcome is different.
"I don’t think there’s been a big difference, although there has been more consistency and the players having confidence helps."
“You need to cut out those silly errors, while also being able to capitalise on your strengths a bit better.
“I don’t think there’s been a big difference, although there has been more consistency and the players having confidence helps.”
Pompey will look to extend their impressive winning run to 10 fixtures when they visit a Coventry side sitting one place higher in fourth spot.
Jackett said: “They’ve only lost three league matches all season, which is a big achievement, although there is a high number of draws.
“We’re very close to them in the table, which makes it an even more interesting game. We’ll look forward to going there.
“We were in control in the fixture at Fratton Park, but conspired to go from 3-1 up to 3-3. We were disappointed not to get the details right.
“But I do feel that both sides are of the required standard to finish the season strongly and really attack the top sides in the league.
“We’ve given ourselves the opportunity to call this is a big contest – rather than sitting in mid-table and planning for next year.”