Defeats for Hull and Lincoln meant that Pompey could have climbed to the League One summit.
But they had to settle for just entering the automatic promotion places after being held to a goalless draw by Fleetwood.
There were not an abundance of clear-cut chances at Fratton Park, although the hosts looked more likely to break the deadlock.
And Kenny Jackett admitted that it was not the most fluent performance from his usually free-scoring side.
The Blues boss said: “It was slightly frustrating and we just couldn’t get going in an attacking sense like I know we’re capable of.
“Maybe that was our decision making and we weren’t able to link cohesively quite as well as we usually do.
"Despite huffing and puffing in the second half, just diddn’t create the chances we needed."
“We had the majority of the game and didn’t really look in any danger, but all the time you can’t score, you’re always worried that a chance can come at the other end.
“I felt we were on top in both halves, without finding our usual link play and balls into the wide areas weren’t very good.
“It was a bit lumpy and not one of our better performances, although we forced their keeper to make a couple of good saves before the break.
“We couldn’t build the momentum from that and despite huffing and puffing in the second half, just didn’t create the chances we needed.
“The players never stopped wanting it and they never stopped trying, so we take the point and move onto Friday.”
Alan Young brandished seven yellow cards in an opening 45 minutes that threatened to boil over at times.
Jackett said: “There were a lot of fouls and also some strange decisions, but the referees have a hard job and we have to take responsibility for our own performance.”