The Blues boss feels his side have ‘gone up a notch’ because new signings have made the difference.
Pompey have recorded two promising efforts in their past two matches.
Jackett’s troops marched to a 2-0 victory against AFC Wimbledon last Saturday, before missing a number of chances in their 3-1 loss at Northampton on Tuesday.
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The Blues dominated the second period at Sixfields through tenacious and harrying pressing.
Championship loanees Stuart O’Keefe, Matty Kennedy and Damien McCrory have all come into the Pompey starting line-up since arriving at Fratton Park on deadline day.
Jackett insists their experience have helped bolster energy levels throughout his side.
The Blues boss said: ‘There’s been more purpose in our last two performances.
‘That is good to see and I want to maintain it.
‘The (energy level) increase has been a combination of players coming in and experience in the right areas.
‘You aspire to have passion and energy and forward momentum.
‘We have seen an increase in that in the past two games.
‘It’s not that it wasn’t there before, but perhaps it was a bit more spasmodic getting that energy and enthusiasm.
‘We want to make sure we can attack teams and look dangerous when we do.
‘Against Northampton, we didn’t get the result, which is the bottom line.
‘But there were a lot of things we have taken from it to work towards a consistent, winning formula.
‘The past two matches we have gone up a notch slightly in all areas of our game.
‘We want to make sure we maintain that.’
Jackett had an overhaul of his squad during the summer.
Gary Roberts and Carl Baker were shown the exit door, despite helping Pompey to the League Two title.
The Blues boss shrunk his average squad age because he reckons a more youthful side gives Pompey a greater chance of being competitive in the third tier.
‘I tried to bring down the average age of the squad because the side that got promoted needed changing,’ Jackett added.
‘I didn’t feel the side that won League Two would have similar success in League One.
‘You have to have an eye to the long term and the changes are both short and long term.’