Cheltenham Town returned home from Fratton Park with what could prove to be a precious point, but once again they will be frustrated having allowed a lead to slip away.
Russell Milton's men fell behind to Matt Tubbs' 17th minute strike, with the poacher tapping in from almost on the line after fine work from Andy Barcham on the Pompey right.
But less than a minute later, they were back on level terms. Matt Richards found Shaun Harrad, who teed up Eliot Richards for his first Robins goal. It was his first since he struck for Tranmere Rovers against his current club last August.
Cheltenham took the lead in the 23rd minute when Matt Richards' free-kick was nodded in by loan defender Will Packwood, who celebrated the first goal of his senior career.
Pompey hit back two minutes before half-time when Matt Richards tripped Danny Hollands and the resulting free-kick from Dan Butler was headed past ex-Portsmouth goalkeeper Trevor Carson by Ryan Taylor, who was a constant aerial threat.
Carson made an excellent save less than a minute after half-time to deny Tubbs a second and Portsmouth were on top for much of the second period, but Cheltenham defended well to secure a share of the spoils.
Troy Brown picked up his 10th yellow card of the season and now faces a two match ban, while Packwood was forced off in the 78th minute after taking a knock, but Milton is hopeful he will be fit to face Exeter City at home on Saturday.
Portsmouth (3-5-2): Jones; Webster (Fodgen 68), Devera, Whatmough; Barcham (East 46), Dunne (McCallum 86), Wallace, Hollands (c), Butler; Tubbs, R Taylor. Subs not used: Cornell (GK), Ertl, Atangana, Chaplin.
Cheltenham Town (4-5-1): Carson; Berry, Packwood (M Taylor 78), Brown (c), Braham-Barrett; E Richards (Wynter 89), Mills, Sparrow, M Richards, Haynes (Kotwica 60); Harrad. Subs not used: Gould (GK), Vaughan, Hanks, Manset.
Referee: D Whitestone.
Attendance: 13,558 (156 away).