Michael Smith came off the bench to hit his first league goal of the season and earn Pompey a point at Cheltenham.
It looked like the Blues would be made to pay for missed opportunities when Daniel O’Shaughnessy fired the hosts ahead midway through the second half.
But Smith capitalised on a goalkeeping error late on to salvage a deserved point and give the large travelling support something to smile about on the journey home.
Paul Cook unsurprisingly stuck with the same side that beat Mansfield at home the previous week.
And they had a chance to open the scoring in the early seconds after Carl Baker swapped passes with Gary Roberts and advanced forward, only to see his shot blocked.
But the hosts immediately broke up the other end and thought they should have won a penalty when Danny Wright hit the turf.
The striker was surrounded by three blue-shirted players, but referee John Brooks decided there had been no infringement.
It was end-to-end stuff in the early stages of the game, with both sides showing plenty of attacking intent.
The chances did dry up to an extent after such a lively opening, although there were still opportunities for the deadlock to be broken.
Kyle Bennett was released into the box on 14 minutes, but it was always going to be tough for him to beat Robins keeper Russell Griffiths from a tight angle.
Meanwhile, a promising move for the hosts ended with Dan Holman blazing over, while the same player later bent a free-kick into the arms of David Forde.
Rose soon hit a cleanly-struck effort on target at the other end, but his shot flew straight at a grateful Griffiths.
Harry Pell wasted a good opportunity for Cheltenham on 32 minutes, dragging wide from the edge of the box after Christian Burgess’ clearance landed at his feet.
But it was the Blues who ended the first half on the ascendency and Griffiths superbly kept out Baker’s diving header after the midfielder had met Gareth Evans’ pin-point delivery.
Roberts then saw a shot bending off target and an onrushing Evans could not quite get there in time to turn the ball back on the right path.
Cheltenham Town 0
Pompey had two great chances to forge ahead straight after the restart, but Griffiths denied them on both occasions.
First the keeper stayed on his feet to save Roberts’ shot after the midfielder had stayed onside to collect Baker’s threaded pass.
Then he prevented Conor Chaplin from heading home Evans’ cross from just a couple of yards out at the far post.
And when Griffiths was unable to frustrate the Blues, the woodwork came to his rescue, with Bennett’s strike coming back off the post.
But the keeper was soon called back into action, quickly smothering the ball before Bennett could reach Roberts’ pass.
Cheltenham had a decent opening of their own just before the hour mark when the visitors failed to deal with a ball sent into their box, but Wright volleyed over from close range.
And it was the Robins who took the lead on 65 minutes after Burgess had been booked for a late challenge on Holman near the halfway line.
James Rowe’s free-kick ricocheted around the Pompey box before eventually landing at the feet of O’Shaughnessy to fire home.
They should have doubled their advantage soon after, but an unmarked Rob Dickie fired wide when the ball found him unmarked in the box.
Cook made an attacking switch to try to inspire a change of fortunes on 75 minutes, with Bennett making way for Smith.
A double substitution then followed moments later, as Noel Hunt and Kal Naismith replaced Chaplin and Roberts.
And Pompey almost immediately found themselves level when the otherwise impressive Griffiths failed to hold Baker’s cross and SMITH reacted quickly to tuck away the loose ball.
Both sides tried their best to find a winner, but with all their previous meetings ending in a draw, it perhaps came as no surprise to see the game end all square.
Cheltenham (3-4-1-2): Griffiths; Dickie, Downes (c), Parslow; Barthram (Suliman 90+1), Pell, Rowe, O’Shaughnessy (Cranston 90+1); Waters; Holman, Wright
Goals: O’Shaughnessy 65
Booked: Pell, Downes
Subs not used: Kitscha, Munns, Whitehead, Morgan-Smith, Arthur
Pompey (4-2-3-1): Forde; Evans, Burgess, Clarke, Stevens; Rose, Doyle (c); Baker, Roberts (Naismith 81), Bennett (Smith 75); Chaplin (Hunt 81)
Goals: Smith 82
Booked: Chaplin, Burgess, Baker
Subs not used: O’Brien, Talbot, Whatmough, Lalkovic
Referee: John Brooks
Attendance: 4,702 (1,537 Pompey fans)