Pompey came away from the Proact Stadium with a goalless draw tonight and it may have been more had Richie Barker's men taken one of the chances they created.
Chesterfield may well be top of the tree but that simply highlights how poor a division that League Two is given that they were outplayed by a Portsmouth side which had conceded five to Scunthorpe not so long ago.
Ricky Holmes was influential in most of Pompey's attacks and forced a good save from goalkeeper Tommy Lee when he flicked Jed Wallace's cross towards goal.
Jake Jervis had the best chance of the half after he brushed aside the Chesterfield full back and cut inside before smashing a shot against the near post, although it would seem that Lee got his hand to the ball.
Pompey remained in control of the first half as the hosts barely tested Trevor Carson, though he had to save a long shot late in the half. It was more than a solid showing from the visitors, however, and Paul Cook's men would surely have to improve during the second half.
They did, to a degree, but the Pompey defence did well to limit their chances as Gary Roberts frustrtatingly fired a shot wide early on.
Jervis had another excellent chance to score as the Spireites' defence gave him space to shoot wide of the far post just before the hour.
Wes Fogden had arguably the best chance of the match as he was put through by Nicky Shorey with an excellent through ball but Lee came out of his goal quickly to block his shot.
Jervis had another chance after Wallace teed the ball up for him but his effort again missed the target and the cynical Pompey fans may have thought that the league leaders would have stolen the victory, although they never really looked like winning the game.
The final whistle blew to end what was one of Pompey's best performances of this calendar year as the home fans left the Proact Stadium frustrated. The travelling fans may be happy with a point but it could well have been all three on another day.
Still, it's a clean sheet against the so-called best side in the league and the team which have scored more goals than any other in League Two. Barker will have won over some of his critics after his team followed his tactical instructions to the letter, with good performances all around the pitch.
The result now means that Portsmouth are now seven points clear of danger although teams below do still have that game in hand, so there is still work to do to be completely sure of League Two survival this season.
But Pompey are gathering some form heading into the rest of the tricky fixtures this month and the fans may well be looking up the table rather than down it in the next few weeks.
Bring on Cheltenham!
Pompey Player Ratings
Trevor Carson: 6 - Little to do, in truth.
Joe Devera: 6 - Solid return to the side.
Ben Chorley: 6 - Comfortable showing.
Bondz N'Gala: 6 - Dealt with everything thrown at him.
Nicky Shorey: 7 - Still looks class.
Jed Wallace: 7 - Involved in some of Pompey's best moves.
Romain Padovani: 6 - Good first half but faded in the second.
Toumani Diagarouga: 7 - Got around the pitch well and won some crucial tackles.
Wes Fogden: 6 - Probably should have done better with his chance to score.
Ricky Holmes: 8 - Gave Chesterfield plenty of problems during the entire match.
Jake Jervis: 6 - Worked hard up front on his own but really should have scored one of the chances he had.
Substitutes
Phil Smith
Sonny Bradley
Marcos Painter
Thery Racon
Johnny Ertl
Ashley Harris
Patrick Agyemang (Jervis 90): N/A - No time to make an impact.