The south coast side has now gone 10 matches in all competitions without a victory.
They blew a golden opportunity to snatch the three points when striker Izale McLeod crashed a penalty against the crossbar after 14 minutes.
Pompey have now drawn three matches on the bounce after a run of seven defeats and Whittingham was pleased with Blues' first shut-out since they defeated Crewe 2-0 on October 13.
He said: "The most pleasing thing from the performance is that we haven't conceded. We needed to make sure we tightened up at Fratton Park because we've been conceding too many goals here and been far too open. That's the reason we've lost games, despite scoring goals."
Whittingham felt Pompey applied enough pressure to collect the win, but said: "When you're down the bottom, every point is a good point.
"I think we had enough chances, enough pressure and I think the way we played was pretty positive. All that was missing was a goal."
Portsmouth will remain in administration until at least January 15 after the court case to determine the potential sale of Fratton Park to the Pompey Supporters Trust was adjourned on Friday. This could leave Whittingham battling to keep his makeshift squad of loanees and short-term signings together.
But asked if he feared a flood of departures, he added: "It's not a major concern. It's in the background. The more immediate concern for us on the pitch is getting points.
"A lot will depend on results. If you're in a football team that's winning games and doing well, then you want to be part of that."