Ceri Hughes, Pompey's new signing from Wimbledon, earned a point in a dour clash with Stockport at Edgeley Park.
Andy Kilner's promotion contenders struggled against the rejuvenated visitors side, who had not won in the last 14 games.
Stockport took the lead through a 14th-minute Tony Dinning penalty.
He coolly chipped the ball over Pompey's debut-making goalkeeper Russell Hoult after Ian Moore had been tripped in the box.
But Portsmouth could have hit back within 10 minutes when Pompey striker Lee Bradbury was bundled over in the box by Jim Gannon.
The striker dusted himself off but crashed his spot kick against the bar.
Stockport controlled the remainder of a scrappy first half with Chris Allen and Aaron Wilbraham, on for the injured Laurent D'Jaffo, having good opportunities to increase the lead.
But, against the run of play, Portsmouth struck back in the 44th minute.
Bradbury, looking to make amends for his earlier miss, jinked past fullback Shane Nicholson on the right and sent over a cross which Hughes, making his debut, nodded in from eight yards out.
The second half started with Portsmouth attacking County at every opportunity, with old war horse Steve Claridge instrumental in most of the good moves.
But Pompey could not beat county keeper Ian Gray and were restricted to a few snap shots to show for their pressure.
County gradually gained some control but the match degenerated into a midfield slog with tempers becoming increasingly frayed.
In one incident a wrestling match started between Stockport's Chris Allen and Pompey's David Waterman.
Referee Alan Kaye took no action except for giving the pair a stern lecture.
Neither team deserved all three points although new Pompey boss Tony Pulis felt his team had created enough chances to win.