Pompey’s youngsters were five minutes away from getting their season back on track after losing their previous two home matches to Liverpool and Coventry.
But with a 2-1 lead and looking well worth the points, sloppy defending let hosts Bristol City in for a late equaliser they barely deserved.
From the start, Bristol so nearly took an early lead as pacy striker Shelton Gooden created an opening for Wesley Burns to flash in a shot which Matt Gledhill anxiously watched as it sped wide.
From the restart, a mix-up between Sam Magri and Adam Webster presented GOODEN with a chance to go clear and thrash an opening goal past Gledhill off the underside of the crossbar.
With the hosts still in the throes of celebration, though, Pompey shook them rigid with a well-worked equaliser as Magri made amends with a superb cross that Ashley HARRIS nodded home at the far post.
Another cut-and-thrust move so nearly earned the young Blues the lead and it took a point-blank save from City keeper Lewis Carey to deny Magri at his near post.
With the interval in sight, City stepped up the pace and Pompey’s defence again came under pressure, although with the efforts of Alex Grant and Dan Butler, they survived with comparative ease.
Early in the second half, Pompey began to dominate and Elliott Wheeler and Harris created a glorious chance for Jed Wallace.
But the recent recruit from Lewes slammed a finish into the arms of Carey rather than taking the easier of option of finding the back of the net.
Moments later, and after having a valid penalty appeal for handball turned down, justice was seen to be done as Harris went down under a tame challenge that resulted in MAGRI stepping up to slam home the spot-kick off the underside of the bar to give the visitors the lead.
Just before the final whistle, though, and having survived a barrage of pressure from Andy Awford’s side, Bristol drew second breath in a last-ditch effort to take something from the match.
And they did just that as Chris Abbott met a cross to head in the equaliser.
BRISTOL CITY: Carey, Sims, Rigg, Abbott, Douglas, Scott, Burns, Wright, Gooden, Gordon, Hall. Subs: Medjedoub, Batton, Miles, Palmer, Kapika.
POMPEY: Gledhill, Magri, Butler, Awford, Webster, Grant, Wheeler, Colson, Harris, Wallace, Higgins. Subs: Cook, Branford, Warren, Burns, Hartson.