Pompey threw away the opportunity for their first away win of the campaign with a 2-2 draw at Cheltenham Town after conceding yet another late goal.
The Blues looked on course for their first win on the road of the new League Two season.
But despite dominating the game for long periods, then sat back in the final 15 minutes to allow their opponents the upper hand as Jermaine McGlashan poked home a stoppage-time leveller.
Pompey started the game brightly taking a fifth-minute lead through Patrick Agyemang as he toe-poked home an opener.
And the Blues striker should have doubled the advantage soon afterwards, blazing over a glorious chance.
But Pompey were hauled back on 36 minutes as McGlashan sprung the offside trap, rounded John Sullivan and finished into an empty net.
The visitors moved ahead again shortly before the interval when Johnny Ertl was on hand to tuck home his first goal for the club, latching on to a low cross.
Pompey started the second half brightly as well and Jed Wallace missed a golden chance for a two-goal cushion after an enterprising run from Andy Barcham.
But the Blues then handed the initiative to the home side as they began to sit deeper and deeper as Cheltenham grew in confidence.
Even though there were no real clear chances, Sullivan was not tested until a ball into the box saw McGlashan somehow get his foot around Danny East and poke beyond a stranded goalkeeper.
And Pompey so nearly went down to defeat as Terry Gornell had the ball in the net again, only for the linesman’s flag to save the day.