A poor first-half display in the Johnstone’s Paint Trophy at Oxford in midweek made way for a much-improved display after the break.
There was a similar pattern at Home Park in the League Two clash with Plymouth on Saturday.
But the Blues boss insisted it was not down to a lack of preparation for the contest and that there was no theme developing.
Instead, he felt his side failed to hit their stride early on as they worked out a way to deal with Plymouth’s wing-back formation.
Whittingham explained: ‘They sprung three at the back on us but once we got used to that, we got our equaliser and came into it a lot more.
‘I think it was the reason behind a slow start. You can put things down on paper, tell players what to do when a ball goes somewhere but they have to get out there and see it for themselves.
‘Then we had more of a chance to describe things to them at half-time.
‘I think they did a lot better in the second half.’
Whittingham also pointed to Plymouth’s system as the reason he chose not to introduce any substitutes in the game.
While some fans were keen to see Andy Barcham brought on for a late burst to search for a winner, Whittingham opted to keep the same personnel.
He said: ‘It was just our shape and the way we were playing.
‘Do you bring someone in new who hasn’t been out there looking at it?
‘If it was a 4-4-2 against a 4-4-2, I might have done it.
‘But the lads who were out there were used to it and were coping pretty well.
‘Do you upset the balance with someone not quite switching on and knowing their system?
‘The lads worked hard against their shape and have got used to it so do you get a fresh pair of legs on to try to score a goal with 10 or 15 minutes to go and possibly leave yourselves open to conceding a goal?
‘I looked at the work-rate that was going on and felt it was better leaving it as it was.’
Although Pompey failed to get into gear early on, it was Yassin Moutaouakil’s error that presented Plymouth’s Conor Hourihane with the opening goal.
But Whittingham was pleased with the French defender’s response to adversity - especially a fine second-half challenge that prevented what could well have been a winner for the home side.
Whittingham said: ‘It was just a lapse. He was trying to chest it back to Trevor (Carson) and it didn’t come off.
‘Whatever it was, he didn’t put his head down and he made up for it with that tackle in the second half.
‘Players can make mistakes and go to pieces.
‘Yassin knows he is important for us and he didn’t do the right thing but he kept trying hard.
‘At the end of the game, you take that one mistake out and he had a decent game.’
Whittingham added: ‘After the week we had I’m happy with a point.
‘We’ve had two good wins and the response to the York game has been great.’