Kenny Jackett insists his Pompey table-toppers aren’t demonstrating signs of being hampered by fatigue.
And the Blues boss has pledged to once more retain his trusted starting XI for Saturday’s crucial clash with Sunderland.
Pompey are presently four points clear at League One’s summit with the half-way point approaching.
It’s encouraging progress achieved by a whole-hearted side largely unchanged and in-tune with each other, while injuries have been sparse.
Craig MacGillivray, Jamal Lowe, Matt Clarke and Lee Brown have been ever-presents during the league campaign, while Tom Naylor and Ronan Curtis have each missed two matches.
Work-rate and energy levels continue to be highly impressive among a team which has topped the table for almost two-and-a-half months.
And Jackett cannot yet see a reason to freshen it up.
He said: ‘I haven’t necessarily got hard and fast rules. You won’t change a side – or you will and rotate. I am neither.
‘At the moment the players look like they are enjoying playing with each other and are into a good groove and hard to beat. We are working hard both in possession and out of possession.
‘If I feel the team needs changing because people are out of form or losing energy than I will do that. I will asses it game by game.
‘I haven't changed it so far, I have been happy assessing players between games, they have not been limping around in the treatment room, they have been out training and looking like they have recovered pretty well from the games.
‘With that assessment in mind, it has been a pretty easy job to keep going.
‘You can overthink it sometimes, but I expect people to dig deep. Similarly, I am sure there will be times when people will need a breather, but it hasn’t come yet.
‘When I listen to managers talking about tiredness, I always wonder that if you tell players they are tired then they will be.
‘There’s a big analysis on the physical output, through sports science and distances run, and the breakdown on that is excellent, it really is excellent. It can help you in terms of the training loads.
‘Similarly, I believe mentally you have to dig deep sometimes. If it gets a little bit tough and you switch off that’s not good, you have to dig deep. And we dug deep at Barnsley.’
The Blues face five matches in the next 15 days – with their Checkatrade Trophy visit to Southend still to be confirmed.
And Jackett is evaluating the players’ fitness levels on a game-by-game by basis.
He added: ‘The league is undoubtedly our number one priority. If I need to rotate in that period I will, but really at the moment my only concentration will be Sunderland.
‘The forward planning around the other games is only through training routines, travelling, generally organisation over the Christmas period and making sure this place is open on the days we want it to be.
‘In terms of team selection, I don’t look that far ahead. We just assess the players, whether it will be substitutions or changes for the next game off the back of Sunderland.’